[tools] Fix python DeprecationWarning: invalid escape sequence

The python documentation says "it’s highly recommended that you use raw strings for all but the simplest expressions." (https://docs.python.org/3/library/re.html)

So do that with the attached patch generated by

    sed -i -e "s/re.search('/re.search(r'/g" $(git grep -l 're.search(')

The warning can be seen in e.g. python3.7:

    $ python3.7 -Wd
    >>> import re; re.search('\s', '')
    <stdin>:1: DeprecationWarning: invalid escape sequence \s

Commited on behalf of Marco Falke.
Differential Revision: https://reviews.llvm.org/D57528


git-svn-id: svn://svn.chromium.org/llvm-project/cfe/trunk/tools/clang-format@353707 0b72dbe1-c17f-4bc7-b9db-2b4152be0356
diff --git a/clang-format-diff.py b/clang-format-diff.py
index 919c09b..3ba0abe 100755
--- a/clang-format-diff.py
+++ b/clang-format-diff.py
@@ -66,7 +66,7 @@
   filename = None
   lines_by_file = {}
   for line in sys.stdin:
-    match = re.search('^\+\+\+\ (.*?/){%s}(\S*)' % args.p, line)
+    match = re.search(r'^\+\+\+\ (.*?/){%s}(\S*)' % args.p, line)
     if match:
       filename = match.group(2)
     if filename == None:
@@ -79,7 +79,7 @@
       if not re.match('^%s$' % args.iregex, filename, re.IGNORECASE):
         continue
 
-    match = re.search('^@@.*\+(\d+)(,(\d+))?', line)
+    match = re.search(r'^@@.*\+(\d+)(,(\d+))?', line)
     if match:
       start_line = int(match.group(1))
       line_count = 1