Fixes #501. Fixes #616 (the original form; not the form in test-data/alias-comment1.zsh which is now considered o be #677 (see previous commit for details)). Fixes a latent bug in test-data/always2.zsh. No user-visible effect, and therefore, no changelog entry.
zsh-syntax-highlighting / highlighters
Navigate into the individual highlighters' documentation to see
what styles ($ZSH_HIGHLIGHT_STYLES keys) each highlighter defines.
Refer to the documentation on highlighters for further information.