pw_presubmit: Allow long lines in blockquotes

Allow long lines in commit messages if they're in blockquotes.

Change-Id: Ic03ddf4399527afd455d2185b889b45b07a87575
Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/125490
Reviewed-by: Wyatt Hepler <hepler@google.com>
Pigweed-Auto-Submit: Rob Mohr <mohrr@google.com>
Commit-Queue: Auto-Submit <auto-submit@pigweed.google.com.iam.gserviceaccount.com>

pw_presubmit/py/pw_presubmit/pigweed_presubmit.py

@@ -866,11 +866,19 @@ def commit_message_format(_: PresubmitContext):
         _LOG.warning('Ignoring Copybara import')
         return
 
-    # Check that the lines are 72 characters or less, but skip any lines that
-    # might possibly have a URL, path, or metadata in them. Also skip any lines
-    # with non-ASCII characters.
+    # Check that the lines are 72 characters or less.
     for i, line in enumerate(lines[2:], 3):
-        if any(c in line for c in ':/>') or not line.isascii():
+        # Skip any lines that might possibly have a URL, path, or metadata in
+        # them.
+        if any(c in line for c in ':/>'):
+            continue
+
+        # Skip any lines with non-ASCII characters.
+        if not line.isascii():
+            continue
+
+        # Skip any blockquoted lines.
+        if line.startswith('  '):
             continue
 
         if len(line) > 72: