Python: Fix highlighting of parentheses

This enables the PythonEditor to handle (un)matching
parentheses correctly.

Change-Id: I31516a5fee922de6b3cfc2254b209739bc42c540
Reviewed-by: David Schulz <david.schulz@qt.io>

src/plugins/python/pythonformattoken.h

@@ -41,6 +41,8 @@ enum Format {
     Format_Identifier,
     Format_Whitespace,
     Format_ImportedModule,
+    Format_LParen,
+    Format_RParen,
 
     Format_FormatsAmount
 };