Fixes a subset of issue #237.

The heretofore code warned once per keypress.

This is related to a future "unbalanced { ( ) }" check for issue #344.

Also adds an XFail test for balanced braces for issue #344.

This was suggested on #355.

This caused warnings with `setopt warn_create_global`.

This manifested in completion of the form «./foo<TAB>» where there happened to
be a program called 'foo' in $PATH.

Fixes #354.
Closes #355.

Fixes #329.

Merge remote-tracking branch 'danielsh/i329-v1'

* danielsh/i329-v1:
  highlighters: Rename entry points.
  driver: Rename highlighter entry points

This tracks the API change made in the previous commit, as suggested in the
(#if 0'd) deprecation warning.

This updates the docs and the driver, in a manner backwards compatible with
existing highlighters.  (None of the highlighters are touched by this change,
yet tests continue to pass.)

Part of issue #329.

Re-fixes #305.

This is a prerequisite for the next commit.

The incumbent code was wrong: the test of $in_redirection in the first hunk
would never have seen «(( in_redirection == 2 ))».  That had no visible
effect since options to sudo don't look like redirection operators.

The structure now mirrors the stall construct at the top of the loop.

Part of issue #305.

This fixes an infinite recursion in zsh without zle-line-pre-redraw [≤5.2] in
the following situation:

% source zsh-syntax-highlighting.zsh
% eval "my-self-insert() { zle -M 'foobar'; ${(q)widgets[self-insert]#*:} \"\$@\" }"
% zle -N self-insert my-self-insert
% source zsh-syntax-highlighting.zsh

Fixes #305.

This patch causes a behaviour difference in the [i257] scenario:

- Before this change, the zle_highlight[isearch] is applied and z-sy-h's
  highlighting isn't.

- With this change, both zle_highlight[isearch] and z-sy-h's
  highlighting are applied, so «echo foo» renders the first word in green
  underline (fg=green from ZSH_HIGHLIGHT_STYLES[builtin], underline from
  zle_highlight[isearch]).

This patch causes the presuppositional FAQ entry added in
a8fe22d422 to be correct.

This is part of #261, of which #288 was a spin-off.

[i257] https://github.com/zsh-users/zsh-syntax-highlighting/pull/257#issuecomment-168394665

* danielsh/m0vie-i288-v2:
  driver: Don't highlight in isearch
  driver: Always bind zle-line-finish and use it instead of accept-*
  driver: Widget binding: Support binding incomplete/nonexistent widgets

zsh version 5.2 and lower don't support ISEARCHMATCH_ACTIVE and
we are unable to re-apply zle_highlight on top. Therefore it is
impossible to see the underlined matched area.

Since that information is more important, completely disable
highlighting in isearch in that case.

To do that, we need to make sure we are actually called when
something changes in isearch.

Trumps #257.

The FAQ entry presupposes #245 will be fixed (in time for the release) too.

Special handling for cursor imprint or partial path highlighting
is needed in more cases than accept-*. For example when accepting
a line from isearch, no accept-* widget is invoked.

The proper way is to use zle-line-finish.

Trumps #259.
Fixes #284.

Merge remote-tracking branch 'upstream/pr/342'

* upstream/pr/342:
  'main': Highlight a broken symlink as a file.
  tests: Add an XFail test for issue #342.

The test passes so I'm adding it directly to master.

Just in case one of the interpolated variables contains a backslash.

Fixes #342.

Suggested-by: Matthew Martin

Makes the text easier to read ("_zsh_highlight_myhighlighter_highlighter" is
a mouthful).

Part of issue #329.

Merge remote-tracking branch 'danielshahaf/i267-linewise-region-v1'

* danielsh/i267-linewise-region-v1:
  tests: Add a regression test for issue #267, concerning highlighting a vi linewise region.
  Support linewise region.

Avoids a fork.