- Extract duplicated code into a new function.
This makes it easier to add support for other entries in the
future, that cannot be accessed in the current version of zsh
(isearch, suffix).
- Make decision logic more comprehensible.
- Respect deliberately empty entries in zle_highlight.
Don't force the default value when the user deliberately sets
an entry in zle_highlight to the empty string.
For example
zle_highligh(paste:)
to disable paste highlighting completely.
Skipping when $cur_widgets == user:$cur_widget was introduced
with 776453cb5b. However there
are cases where this is not just an 'already rebound' event, but
simply a normal widget whose function name happens to be identical
to its widget name.
Example:
expand-absolute-path is a widget whose function name is also
expand-absolute-path. No reason why this should be ignored.
Another example:
edit-command-line
Just because a widget starts with _ does not mean it should be
skipped when rebinding. The only reason widgets need to be skipped
is when their function name start with _zsh_highlight_widget*,
which is checked later.
Example:
_expand_alias (^Xa) needs to be wrapped.
The exclusion of _* was introduced in 186d80054a
to fix#65, but it is not needed. The relevant exclusion of
_zsh_highlight_widget* is already enough due to the case statement.
