runtime(vim): Update base-syntax, improve function definition highlighting (vim/vim#14203)
Improve function definition highlighting.
- Match bang and function modifiers - abort etc.
- Only match valid scope modifiers.
- Match listing commands.
- Don't match ex commands in function names.
- Split function syntax groups into :func and :def subgroups.
- Match Vim9-script parameter and return types.
- Limit legacy-script and Vim9-script comments to :func and :def
definitions, respectively.
35e6f4ca27
Omit the vimFunctionError change as it's a whitespace-only change and
will likely be superseded by later patches.
Co-authored-by: dkearns <dougkearns@gmail.com>