Commit: runtime(sh): Update sh syntax and add shDerefOffset to shDerefVarArray for bash (#13480)

[Christian Brabandt]

runtime(sh): Update sh syntax and add shDerefOffset to shDerefVarArray for bash (#13480)

Commit: https://github.com/vim/vim/commit/ce3b0136c6d9d09af41969d3dc9634f115505a32
Author: Lucien Grondin <gron...@yahoo.fr>
Date: Sat Nov 4 09:41:37 2023 +0100

runtime(sh): Update sh syntax and add shDerefOffset to shDerefVarArray for bash (https://github.com/vim/vim/issues/13480)

Add shDerefOffset to shDerefVarArray.

Example code:

```bash
declare -a a=({a..z})

echo "${a[@]:1:3}"
```


Signed-off-by: Christian Brabandt <c...@256bit.org>

diff --git a/runtime/syntax/sh.vim b/runtime/syntax/sh.vim
index 0fb10f0e5..e2b194719 100644
--- a/runtime/syntax/sh.vim
+++ b/runtime/syntax/sh.vim
@@ -531,7 +531,7 @@ if exists("b:is_kornshell") || exists("b:is_posix")
endif

" sh ksh bash : ${var[... ]...} array reference: {{{1
-syn region shDerefVarArray contained matchgroup=shDeref start="\[" end="]" contains=@shCommandSubList nextgroup=shDerefOp,shDerefOpError
+syn region shDerefVarArray contained matchgroup=shDeref start="\[" end="]" contains=@shCommandSubList nextgroup=shDerefOp,shDerefOpError,shDerefOffset

" Special ${parameter OPERATOR word} handling: {{{1
" sh ksh bash : ${parameter:-word} word is default value