Fix: Syntax highlighting for various issues (#2810)

* 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

runtime/syntax/vi.yaml

@@ -4,12 +4,18 @@ detect:
     filename: "(^|/|\\.)(ex|vim)rc$|\\.vim"
 
 rules:
-    - identifier: "[A-Za-z_][A-Za-z0-9_]*[[:space:]]*[()]"
+    - identifier: "[A-Za-z_][A-Za-z0-9_]*[(]+[A-Za-z0-9_:.,\\s]*[)]+"
+    - special: "[()]+"
     - statement: "\\b([nvxsoilc]?(nore|un)?map|[nvlx]n|[ico]?no|[cilovx][um]|s?unm)\\b"
-    - statement: "\\b(snor|nun|nm|set|if|endif|let|unlet)\\b"
-    - statement: "[!&=]"
+    - statement: "\\b(snor|nun|nm|set|if|endif|let|unlet|source)\\b"
+    - statement: "[!&=?]"
     - constant.number: "\\b[0-9]+\\b"
 
+    - comment:
+        start: "(^\"|[ \t]+\" |[ \t]+\"$)"
+        end: "$"
+        rules: []
+
     - constant.string:
         start: "\""
         end: "\""
@@ -23,10 +29,3 @@ rules:
         skip: "\\\\."
         rules:
             - constant.specialChar: "\\\\."
-
-    - comment:
-        start: "\""
-        end: "$"
-        rules: []
-        
-