runtime(sh): Fix various syntax highlighting problems in ksh93 scripts

runtime(sh): Fix various syntax highlighting problems in ksh93 scripts

- Fixed syntax highlighting for ksh93 namespace variables starting
  with '${.'
- Added support for the alarm, eloop, fds, mkservice, pids, poll and
  sha2sum builtins (which are indeed ksh93 builtins, albeit whether or
  not they are available depends on the ksh release and the compiled
  SHOPT options).
- Added support for the many Unix commands provided by ksh93's libcmd
  as builtin commands (since these are general commands, scripts for
  other shells like bash will also highlight these).
  - The dumps for the sh_0{2,5,6,8,9}.sh were recreated due to this
    change affecting commands those scripts call (e.g. 'wc').
- Enabled ${parameter/pattern/string} and friends for ksh syntax.
- Enabled case modification for ksh. See also:
  https://github.com/ksh93/ksh/commit/c1762e03
- Enabled ;;& support for ksh. See also:
  https://github.com/ksh93/ksh/commit/fc89d20a
- Added many special ksh variables using 93u+m's data/variables.c
  as a reference.

If vim can't figure out which ksh release is in play using e.g.
the hashbang path, in such a case a generic default that enables
everything and the kitchen sink will be used. Otherwise, features will
be disabled if it's absolutely known a certain feature will not be
present. Examples:
   - ERRNO is ksh88 specific, so that is locked to ksh88.
   - Only 93u+m (assumed for generic) has SRANDOM, and only 93u+m
     and 93v- have case modification support.
   - 93u+ and 93v- have VPATH and CSWIDTH variables (the latter
     is vestigal, but still present in the hardcoded variable table).
   - 93v- and ksh2020 have (buggy and near unusable) implementations
     of compgen and complete.
   - Only mksh provides function substitutions, i.e. ${|command;}.

This took the better part of my day to implement. It seems to work well
enough though. (Also had to regenerate the dumps again while testing
it, as now there are dup scripts with mere hashbang differences, used
solely for testing syntax highlighting differences.)

closes: #17348

Signed-off-by: Johnothan King <johnothanking@protonmail.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>