fix hashtags: double colons are not hashtags

Bug: 896110
Change-Id: Ibaf36df48d9ea25e8ee633ca505fa7f7c2063df4
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/tools/depot_tools/+/1944639
Reviewed-by: Edward Lesmes <ehmaldonado@chromium.org>
Commit-Queue: Anthony Polito <apolito@google.com>
diff --git a/git_cl.py b/git_cl.py
index 8fa7dd9..505a3e8 100755
--- a/git_cl.py
+++ b/git_cl.py
@@ -2830,7 +2830,7 @@
   CHERRY_PICK_LINE = r'^\(cherry picked from commit [a-fA-F0-9]{40}\)$'
   STRIP_HASH_TAG_PREFIX = r'^(\s*(revert|reland)( "|:)?\s*)*'
   BRACKET_HASH_TAG = r'\s*\[([^\[\]]+)\]'
-  COLON_SEPARATED_HASH_TAG = r'^([a-zA-Z0-9_\- ]+):'
+  COLON_SEPARATED_HASH_TAG = r'^([a-zA-Z0-9_\- ]+):($|[^:])'
   BAD_HASH_TAG_CHUNK = r'[^a-zA-Z0-9]+'
 
   def __init__(self, description, bug=None, fixed=None):