Fix #83: Match function extensions with (?=\\([^\\)]+=>)

Author: nicolasstucki

src/typescript/Scala.tmLanguage.ts

@@ -847,7 +847,7 @@ export const scalaTmLanguage: TmLanguage = {
     inheritance: {
       patterns: [
         {
-          match: '(extends|with|derives)\\s+([^\\s\\{\\[\\]]+)',
+          match: '(extends|with|derives)\\s+([^\\s\\(\\{\\[\\]]+|(?=\\([^\\)]+=>))',
           captures: {
             '1': {
               name: 'keyword.declaration.scala'