simplify regex

Author: kaspersv

config/add-overlay-annotations.py

@@ -20,7 +20,7 @@
 import re
 from difflib import context_diff
 
-OVERLAY_PATTERN = re.compile(r'overlay\[[a-zA-Z0-9?_\\-]+\]')
+OVERLAY_PATTERN = re.compile(r'overlay\[[a-zA-Z?_-]+\]')
 
 def has_overlay_annotations(lines):
     '''