* highlighter: Fix region & pattern detection
* syntax/sh: Highlight upper case options too
* syntax/c(pp): Try to synchronize the rules to lower the maintenance effort
* syntax/ruby: Fix explicit filename detection in directories
* highlighter: Respect skip rules in regions
* syntax/sh: Fix parameter expansion, cond. flags and generalize filename via ""
* syntax/php|vi: Correct strings in comments to comments only
Additionally improve vimscript comment handling.
* highlighter: Remove problematic start|end check in find(all)Index()
...and additionally remove recursive region end detection
Use the 'regexp2' library for lookahead and lookbehind in region
start and end regular expressions to support things like closing quotes
that aren't preceded by backslashes.
