The change of behaviour is triggered by test-data/sudo-redirection.zsh: the iteration
on "otheruser" sets $next_word to ":regular::sudo_opt::start::sudo_opt::start:" before
this patch, but to ":regular::sudo_opt::start:" after it (note the deduplication).

The fix for issue #9 was accidentally broken by the penultimate commit.

Note that we don't care about aliases to ZSH_HIGHLIGHT_TOKENS_COMMANDSEPARATOR
entries, since the code deals with aliases at command position.

Use this to remove [path_prefix] highlighting during accept-* widgets.
This causes ": file.tx<CR>" to remove the underline from "file.tx", like
": file.tx<SPACE>" already does.  (Assume 'file.txt' exists.)

Fixes zsh-users/zsh-syntax-highlighting#187.
Adds a test for zsh-users/zsh-syntax-highlighting#204.

Followup to b2ac98b981.

Update expectations on the subshell test (which triggered this bug, since it has
a passing test point following a 'todo' test point).

Make the test pass by setting explicitly the global state (existing $HOME) it
depends on.  Test another value of the global state (a non-existing $HOME).

Follow-up to the last commit.

E: zsh-syntax-highlighting: missing-dep-for-interpreter zsh => zsh | zsh-beta (usr/share/zsh-syntax-highlighting/highlighters/main/main-highlighter.zsh)
W: zsh-syntax-highlighting: executable-not-elf-or-script usr/share/zsh-syntax-highlighting/highlighters/main/main-highlighter.zsh

All these files should be sourced, not executed; and Debian's lintian complains:

W: zsh-syntax-highlighting: script-not-executable usr/share/zsh-syntax-highlighting/zsh-syntax-highlighting.zsh

This causes '~/bin/foo' to highlight as a command, rather than as a file.

Part of issue #201.

Fixes zsh-users/zsh-syntax-highlighting#147.

Fixes zsh-users/zsh-syntax-highlighting#188 in the case that both the
opening '((' and closing '))' have been typed,  The case that only the
opening '((' have been typed is also fixed, but requires a zsh development
build (zsh-5.1.1-52-g4bed2cf or newer); see comments within.

Fixes zsh-users/zsh-syntax-highlighting#193.

Followup to 219184f046d40cc723606797666dab18f8a6aea7, which fixed issue #196.

Related to issue #205.

Without this, redirections, history expansions, and command separators would
be matched by path_approx.

A test case is simply LBUFFER="<" RBUFFER="" (highlighted as redirection with this
fix and as path_approx without it).

Fixes zsh-users/zsh-syntax-highlighting#204.

Highlight the last character of a «\xHH» escape when it is the last thing in
LBUFFER.  This is similar to what b0cc02ed86 did
for issue #186.

A leading zero, as in '\0NNN', is permitted by 'echo' but not by 'print',
and «$''» follows 'print'.

A leading zero is not permitted in the '\xHH' syntax.

Character class syntax does not ignore commas between ranges.

Correct highlighting of backslash escapes within "" strings: highlight only
the four specific escape sequences defined there.

Fixes zsh-users/zsh-syntax-highlighting#196.