pw_watch: Add missing commas

Change-Id: I2d32db661a58492535bae91cc25500241d304d55
Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/17400
Commit-Queue: Rob Mohr <mohrr@google.com>
Commit-Queue: Keir Mierle <keir@google.com>
Reviewed-by: Keir Mierle <keir@google.com>
diff --git a/pw_watch/py/pw_watch/watch.py b/pw_watch/py/pw_watch/watch.py
index ffc1aa0..092ab3c 100755
--- a/pw_watch/py/pw_watch/watch.py
+++ b/pw_watch/py/pw_watch/watch.py
@@ -448,10 +448,10 @@
     pigweed_exclude_list = [
         pw_root_dir / ignored_directory for ignored_directory in [
             '.environment',  # Bootstrap-created CIPD and Python venv.
-            '.presubmit'  # Presubmit-created CIPD and Python venv.
+            '.presubmit',  # Presubmit-created CIPD and Python venv.
             '.git',  # Pigweed's git repo.
-            '.mypy_cache'  # Python static analyzer.
-            '.cargo'  # Rust package manager.
+            '.mypy_cache',  # Python static analyzer.
+            '.cargo',  # Rust package manager.
             'out',  # Typical build directory.
         ]
     ]