Use Raw Python Strings for Regex in Python

Was seeing a lot of SyntaxWarnings when building as some regex
strings were not raw strings and thus were showing invalid escape
sequences due to (python/cpython#98401).
These are just warnings now on Python 3.12, but will become errors
in the future. Fixing now to prevent builds breaking. It seems the
files are mostly following this convention now, so this makes the
non raw strings consistent.

Change-Id: Ia8eacfd353c41a6c1d8e0482f3b7fbd4dc7a93e1
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5832811
Reviewed-by: Mihai Sardarescu <msarda@chromium.org>
Commit-Queue: Andrew Grieve <agrieve@chromium.org>
Reviewed-by: Andrew Grieve <agrieve@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1352933}


CrOS-Libchrome-Original-Commit: 31f4229550ffa8f15f7a5da9b67a84cc4f4eb757

build/android/gyp/util/resources_parser.py

@@ -19,7 +19,7 @@
 
 
 def _ResourceNameToJavaSymbol(resource_name):
-  return re.sub('[\.:]', '_', resource_name)
+  return re.sub(r'[\.:]', '_', resource_name)
 
 
 class RTxtGenerator: