I just noticed there's already an option to watch the input files.

eg. here's a commit where @damienmg improved how it's wired on Mac:
bazelbuild/bazel@990fa00

But IIUC that option doesn't actually put Bazel in watch mode.

1. does ibazel benefit from using that flag as well?
2. should we add docs on that flag to clarify that it's not a watch mode and maybe point here?