Improve new syntax files and fix a region glitch

runtime/syntax/vi.yaml

@@ -1,13 +1,29 @@
 filetype: vi
 
-detect: 
+detect:
     filename: "(^|/|\\.)(ex|vim)rc$|\\.vim"
 
 rules:
     - identifier: "[A-Za-z_][A-Za-z0-9_]*[[:space:]]*[()]"
     - 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"
-    - symbol.operator: "[!&=]"
-    - constant.string: "\"(\\\\.|[^\"])*\"|'(\\\\.|[^'])*'"
+    - statement: "[!&=]"
     - constant.number: "\\b[0-9]+\\b"
-    - comment: "(^|[[:space:]])\\\"[^\"]*$"
+
+    - constant.string:
+        start: "\""
+        end: "\""
+        rules:
+            - constant.specialChar: "\\\\."
+
+    - constant.string:
+        start: "'"
+        end: "'"
+        rules:
+            - constant.specialChar: "\\\\."
+
+    - constant.comment:
+        start: "\""
+        end: "$"
+        rules: []
+