341a3ae1f0
_zsh_highlight_add_highlight appends to region_highlight $1 $2 and the next non-null parameter. If there is no non-null parameter, do nothing, This is so that highlighters can add a style with fallbacks if the most specific style is not defined. If none of the applicable styles are defined, do the right thing and don't add an invalid entry to region_highlight. The pattern highlighter doesn't use this function as it'd need too large of an API change.
zsh-syntax-highlighting / highlighters
Navigate into the individual highlighters' documentation to see
what styles ($ZSH_HIGHLIGHT_STYLES keys) each highlighter defines.
Refer to the documentation on highlighters for further information.