pw_presubmit: Better formatting for long times

Change-Id: I3f5ed338718ede5a93900217bd7b4fbe31159c26
Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/33120
Pigweed-Auto-Submit: Rob Mohr <mohrr@google.com>
Commit-Queue: Auto-Submit <auto-submit@pigweed.google.com.iam.gserviceaccount.com>
Reviewed-by: Keir Mierle <keir@google.com>
diff --git a/pw_presubmit/py/pw_presubmit/presubmit.py b/pw_presubmit/py/pw_presubmit/presubmit.py
index a572a9a..5ddddf5 100644
--- a/pw_presubmit/py/pw_presubmit/presubmit.py
+++ b/pw_presubmit/py/pw_presubmit/presubmit.py
@@ -83,7 +83,10 @@
 
 def _format_time(time_s: float) -> str:
     minutes, seconds = divmod(time_s, 60)
-    return f' {int(minutes)}:{seconds:04.1f}'
+    if minutes < 60:
+        return f' {int(minutes)}:{seconds:04.1f}'
+    hours, minutes = divmod(minutes, 60)
+    return f'{int(hours):d}:{int(minutes):02}:{int(seconds):02}'
 
 
 def _box(style, left, middle, right, box=tools.make_box('><>')) -> str: