Remove 2.13.0a0 entries from 2.14.0.dev0 release notes (#15955)
Remove 2.13.0a0 entries from 2.14.0.dev0 release notes (#15955)

I suspect `changelog.py` was unintentionally run with `--old=2.13.0.dev5`, given that `a0` is a new thing.
benjyw/pants,pantsbuild/pants,pantsbuild/pants,pantsbuild/pants,pantsbuild/pants,benjyw/pants,benjyw/pants,benjyw/pants,benjyw/pants,benjyw/pants,pantsbuild/pants,pantsbuild/pants,pantsbuild/pants,benjyw/pants