While writing docs in #54642, I
became dis-satisfied with how `MemoryRef` currently works and since we
are approaching the deadline for changing things around here, made this.

Previously, we had the builtin `memoryref` which constructed a
`GenericMemoryRef` from a `GenericMemory` or from a `GenericMemoryRef`
and an offset. and then we defined constructors `GenericMemoryRef`,
`MemoryRef` etc that provided a nicish interface around the intrinsic.
The problem with this is that people who want to make a
`GenericMemoryRef` don't care what kind of `GenericMemoryRef` they are
making. That choice is defined by the `GemericMemory`. As such, I have
switched it around so that now the intrinsic is named `memoryrefnew`
which frees up `memoryref` to be the function that constructs the
appropriate type of `GenericMemoryRef`.

This could have been done purely on the Base side, but renaming the
intrinsic seems worth it to me since Base/Core use the (new) `memoryref`
a lot and it seems like we should make the experience the same for
internal and external users rather than making `Base` have to work
around a bad name.

Closes #53854. After talking
with @vtjnash, we are ready to commit to the `GenericMemory` interface.
Sorry @nsajko that this took me so long to get around to.

---------

Co-authored-by: Marek Kaluba <kalmar@mailbox.org>
Co-authored-by: Neven Sajko <s@purelymail.com>
(cherry picked from commit 589fd1a)

While writing docs in #54642, I
became dis-satisfied with how `MemoryRef` currently works and since we
are approaching the deadline for changing things around here, made this.

Previously, we had the builtin `memoryref` which constructed a
`GenericMemoryRef` from a `GenericMemory` or from a `GenericMemoryRef`
and an offset. and then we defined constructors `GenericMemoryRef`,
`MemoryRef` etc that provided a nicish interface around the intrinsic.
The problem with this is that people who want to make a
`GenericMemoryRef` don't care what kind of `GenericMemoryRef` they are
making. That choice is defined by the `GemericMemory`. As such, I have
switched it around so that now the intrinsic is named `memoryrefnew`
which frees up `memoryref` to be the function that constructs the
appropriate type of `GenericMemoryRef`.

This could have been done purely on the Base side, but renaming the
intrinsic seems worth it to me since Base/Core use the (new) `memoryref`
a lot and it seems like we should make the experience the same for
internal and external users rather than making `Base` have to work
around a bad name.

(cherry picked from commit fa038d9)

Backported PRs:
- [x] #54361 <!-- [LBT] Upgrade to v5.9.0 -->
- [x] #54474 <!-- Unalias source from dest in copytrito -->
- [x] #54548 <!-- Fixes for bitcast bugs with LLVM 17 / opaque pointers
-->
- [x] #54191 <!-- make `AbstractPipe` public -->
- [x] #53402 <!-- Add `jl_getaffinity` and `jl_setaffinity` -->
- [x] #53356 <!-- Rename at-scriptdir project argument to at-script and
search upwards for Project.toml -->
- [x] #54545 <!-- typeintersect: fix incorrect innervar handling under
circular env -->
- [x] #54586 <!-- Set storage class of julia globals to dllimport on
windows to avoid auto-import weirdness. Forward port of #54572 -->
- [x] #54587 <!-- Accomodate for rectangular matrices in `copytrito!`
-->
- [x] #54617 <!-- CLI: Use `GetModuleHandleExW` to locate libjulia.dll
-->
- [x] #54605 <!-- Allow libquadmath to also fail as it is not available
on all systems -->
- [x] #54634 <!-- Fix trampoline assembly for build on clang 18 on apple
silicon -->
- [x] #54635 <!-- Aggressive constprop in trevc! to stabilize triangular
eigvec -->
- [x] #54645 <!-- ensure we set the right value to gc_first_tid -->
- [x] #54554 <!-- make elsize public -->
- [x] #54648 <!-- Construct LazyString in error paths for tridiag -->
- [x] #54658 <!-- fix missing uuid check on extension when finding the
location of an extension -->
- [x] #54594 <!-- Switch to Pkg mode prompt immediately and load Pkg in
the background -->
- [x] #54669 <!-- Improve error message in inplace transpose -->
- [x] #54671 <!-- Add boundscheck in bindingkey_eq to avoid OOB access
due to data race -->
- [x] #54672 <!-- make: Fix `sed` command for LLVM libraries with no
symbol versioning -->
- [x] #54624 <!-- more precise aliasing checks for SubArray -->
- [x] #54679 <!-- 🤖 [master] Bump the Distributed stdlib from 6a07d98 to
6c7cdb5 -->
- [x] #54604 <!-- Fix tbaa annotation on union selector bytes inside of
structs -->
- [x] #54690 <!-- Fix assertion/crash when optimizing function with dead
basic block -->
- [x] #54704 <!-- LazyString in reinterpretarray error messages -->
- [x] #54718 <!-- fix prepend StackOverflow issue -->
- [x] #54674 <!-- Reimplement dummy pkg prompt as standard prompt -->
- [x] #54737 <!-- LazyString in interpolated error messages involving
types -->
- [x] #54642 <!-- Document GenericMemory and AtomicMemory -->
- [x] #54713 <!-- make: use `readelf` for LLVM symbol version detection
-->
- [x] #54760 <!-- REPL: improve prompt! async function handler -->
- [x] #54606 <!-- fix double-counting and non-deterministic results in
`summarysize` -->
- [x] #54759 <!-- REPL: Fully populate the dummy Pkg prompt -->
- [x] #54702 <!-- lowering: Recognize argument destructuring inside
macro hygiene -->
- [x] #54678 <!-- Don't let setglobal! implicitly create bindings -->
- [x] #54730 <!-- Fix uuidkey of exts in fast path of `require_stdlib`
-->
- [x] #54765 <!-- Handle no-postdominator case in finalizer pass -->
- [x] #54591 <!-- Don't expose guard pages to malloc_stack API consumers
-->
- [x] #54755 <!-- [TOML] remove Dates hack, replace with explicit usage
-->
- [x] #54721 <!-- add try/catch around scheduler to reset sleep state
-->
- [x] #54631 <!-- Avoid concatenating LazyString in setindex! for
triangular matrices -->
- [x] #54322 <!-- effects: add new `@consistent_overlay` macro -->
- [x] #54785
- [x] #54865
- [x] #54815
- [x] #54795
- [x] #54779
- [x] #54837 

Contains multiple commits, manual intervention needed:
- [ ] #52694 <!-- Reinstate similar for AbstractQ for backward
compatibility -->
- [ ] #54649 <!-- Less restrictive copyto! signature for triangular
matrices -->

Non-merged PRs with backport label:
- [ ] #54779 <!-- make recommendation clearer on manifest version
mismatch -->
- [ ] #54739 <!-- finish implementation of upgradable stdlibs -->
- [ ] #54738 <!-- serialization: fix relocatability bug -->
- [ ] #54574 <!-- Make ScopedValues public -->
- [ ] #54457 <!-- Make `String(::Memory)` copy -->
- [ ] #53957 <!-- tweak how filtering is done for what packages should
be precompiled -->
- [ ] #53452 <!-- RFC: allow Tuple{Union{}}, returning Union{} -->
- [ ] #53286 <!-- Raise an error when using `include_dependency` with
non-existent file or directory -->
- [ ] #51479 <!-- prevent code loading from lookin in the versioned
environment when building Julia -->

Following the discussion in #54642

Implemented:
- [x] `modifyindex_atomic!`, `swapindex_atomic!`, `replaceindex_atomic!`
for `GenericMemory`
- [x] `getindex_atomic`, `setindex_atomic!`, `setindexonce_atomic!` for
`GenericMemory`
- [x] add support for references in `@atomic` macros
- [x] add support for vararg indices in `@atomic` macros 
- [x] tests
- [x] update docstrings with example usage
- ~[ ] update Atomics section of the manual (?)~
- [x] news

@oscardssmith @vtjnash 

# New `@atomic` transformations implemented here:
```julia
julia> @macroexpand (@atomic a[i1,i2])
:(Base.getindex_atomic(a, :sequentially_consistent, i1, i2))

julia> @macroexpand (@atomic order a[i1,i2])
:(Base.getindex_atomic(a, order, i1, i2))

julia> @macroexpand (@atomic a[i1,i2] = 2.0)
:(Base.setindex_atomic!(a, :sequentially_consistent, 2.0, i1, i2))

julia> @macroexpand (@atomic order a[i1,i2] = 2.0)
:(Base.setindex_atomic!(a, order, 2.0, i1, i2))

julia> @macroexpand (@AtomicSwap a[i1,i2] = 2.0)
:(Base.swapindex_atomic!(a, :sequentially_consistent, 2.0, i1, i2))

julia> @macroexpand (@AtomicSwap order a[i1,i2] = 2.0)
:(Base.swapindex_atomic!(a, order, 2.0, i1, i2))

julia> @macroexpand (@atomic a[i1,i2] += 2.0)
:((Base.modifyindex_atomic!(a, :sequentially_consistent, +, 2.0, i1, i2))[2])

julia> @macroexpand (@atomic order a[i1,i2] += 2.0)
:((Base.modifyindex_atomic!(a, order, +, 2.0, i1, i2))[2])

julia> @macroexpand (@atomiconce a[i1,i2] = 2.0)
:(Base.setindexonce_atomic!(a, :sequentially_consistent, :sequentially_consistent, 2.0, i1, i2))

julia> @macroexpand (@atomiconce o1 o2 a[i1,i2] = 2.0)
:(Base.setindexonce_atomic!(a, o1, o2, 2.0, i1, i2))

julia> @macroexpand (@atomicreplace a[i1,i2] (2.0=>3.0))
:(Base.replaceindex_atomic!(a, :sequentially_consistent, :sequentially_consistent, 2.0, 3.0, i1, i2))

julia> @macroexpand (@atomicreplace o1 o2 a[i1,i2] (2.0=>3.0))
:(Base.replaceindex_atomic!(a, o1, o2, 2.0, 3.0, i1, i2))

```

---------

Co-authored-by: Oscar Smith <oscardssmith@gmail.com>