* fix Bash completion on macOS
The Homebrew-provided bash-completion is version 1.x,
which doesn't provide _init_completion. We add a standard
shim instead.
* Add entry to CHANGELOG
* Update CHANGELOG.md
Co-authored-by: Ville Skyttä <ville.skytta@iki.fi>
* review: avoid calling _split_longopt repeatedly
Co-authored-by: Ville Skyttä <ville.skytta@iki.fi>