This commit updates the README to remove @pyrmont as a maintainer. He
stepped down as a maintainer from 7 December 2020.

…rono literals with digit separator (#1665)

Co-authored-by: Stuart <stuart.wheaton@jhuapl.edu>

* Update README.md

Add installation instructions

* Remove gem version as requested

…JSL lexer (#1663)

* fix lexing of one line block comments

* better parsing of scoped variables/functions

* missing return

* add more jsl visual samples

* simplify multiline comment rule
use non greedy .*

Co-authored-by: Ben Peachey Higdon <bpeachey@predictum.com>

This fixes the warning:

```
lib/rouge/formatter.rb:46: warning: Using the last argument as
keyword parameters is deprecated; maybe ** should be added to the call
```

More details:
https://www.ruby-lang.org/en/news/2019/12/12/separation-of-positional-and-keyword-arguments-in-ruby-3-0/

The regex is lifted from the YamlLexer class in Pygments library.

`power_assert` recently released version 2.0 which caused some
issues on older versions of Ruby. Pin to 1.2 for now until we
deprecate support for older versions of Ruby.

* Avoid catastrophic backtracing in regex

* Update factor lexer string regex

Uses the same regex as pygments, and removes the
triple quote regex, which isn't actually supported
in factor