Make regex lookahead check more strict

TypeScript.YAML-tmLanguage

@@ -140,7 +140,7 @@ variables:
     {{functionLikeType}} |
     (:\s*(=>|{{matchingParenthesis}}|(<[^<>]*>)|[^<>(),=])+={{functionOrArrowLookup}})
   arrowFunctionEnd: (?==>|\{|(^\s*(export|function|class|interface|let|var|{{usingKeyword}}|{{awaitUsingKeyword}}|const|import|enum|namespace|module|type|abstract|declare)\s+))
-  regexpTail: ([dgimsuy]+|(?![\/\*])|(?=\/\*))(?!\s*[a-zA-Z0-9_$])
+  regexpTail: (?!\*)[dgimsuy]*((?!\/)|(?=\/\*))(?!\s*[a-zA-Z0-9_$])
   completeRegexp: \/(?![\/*])(?=(?:[^\/\\\[]|\\.|\[([^\]\\]|\\.)*\])+\/{{regexpTail}})
 
 patterns:

tests/baselines/Issue1024.baseline.txt

@@ -0,0 +1,34 @@
+original file
+-----------------------------------
+1
+	/ f(/u/g);
+-----------------------------------
+
+Grammar: TypeScript.tmLanguage
+-----------------------------------
+>1
+ ^
+ source.ts constant.numeric.decimal.ts
+>	/ f(/u/g);
+ ^
+ source.ts
+  ^
+  source.ts keyword.operator.arithmetic.ts
+   ^
+   source.ts
+    ^
+    source.ts meta.function-call.ts entity.name.function.ts
+     ^
+     source.ts meta.brace.round.ts
+      ^
+      source.ts string.regexp.ts punctuation.definition.string.begin.ts
+       ^
+       source.ts string.regexp.ts
+        ^
+        source.ts string.regexp.ts punctuation.definition.string.end.ts
+         ^
+         source.ts string.regexp.ts keyword.other.ts
+          ^
+          source.ts meta.brace.round.t
+           ^
+           source.ts punctuation.terminator.statement.ts

tests/cases/Issue1024.ts

@@ -0,0 +1,2 @@
+1
+	/ f(/u/g);