Closes #291.

* commit '2f18ba':
  'main': use zsh/parameter to resolve alias
  driver: load zsh/parameter if available

If possible, use zsh/parameter to avoid forks.

Fixes #263.

* upstream/pr/308:
  'main': Fix issue #302, "Process substitution misparsed as redirection".
  'main': Factor out common code.  No functional change.
  'main': Add a regression test for issue #302, "Process substitution misparsed as redirection".

Follow-up to 2176692704.

Part of #306.

Found-by: m0viefreak
(in #298)

* upstream/pr/315:
  'main': optimization that in my tests shows 2.7s -> 2.2s

Consider indexing long buffers (say 300 chars). E.g. following line:
      integer offset=${${buf[start_pos+1,len]}[(i)$needle]}
will gradually go into large indices for first index [a,] and be kept
at large index for second index [,b]. Instead, we can remove already
processed characters from buf:
    proc_buf="${proc_buf[offset + $#arg + 1,-1]}"
$offset and $#arg are small, first index will not be large. $proc_buf
will be smaller and smaller and the second index [,-1] will run shorter
and shorter.

Keep references in prose as '~/.zshrc': using $ZDOTDIR in that context would
be confusing, and people who set $ZDOTDIR understand these references.

This also removes an implicit assumption that ~/.zshrc is idempotent.

Inspired by #312.

Use correct indexing also for cursor-matchingbracket.

Fixup for 95d82568d8

Part of #306

ISEARCH_ACTIVE was renamed ISEARCHMATCH_ACTIVE in workers/38921
(commit f06be0ffcf2c to zsh itself).

Fixes #299.

Closes #297.

Use 'print -r --' instead, so literal backslashes in $BUFFER aren't expanded.

Found-by: Matthew Martin

The new output improves readability of the 'main' highlighter's test output.

Without this when bracket_color_size is 0,
    $(( (levelpos[$pos] - 1) % bracket_color_size + 1 ))
errors with division by zero.

Since the _zsh_highlight_add_highlight that the tests use ignores
ZSH_HIGHLIGHT_STYLES, we can test both an injective mapping and an empty
mapping at once.

Closes #287. Testing the keys directly removes the need for
unused_highlight which will be removed next.

This removes the need for the typepos array.

zsh arrays start at one, and this will make the next commit easier.

Review-by: Matthew Martin

'none' is a valid highlighting type. Since by convention styles are all
lowercase, 'NONE' shouldn't conflict with anything.

Closes #289.

_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.