Fix format_duration

format_duration did not properly format hours and minutes. Add the
necessary string format specifiers.

Change-Id: Ied27e732f8ff7cd6ef6722c94d38ea0907cdee40
Reviewed-on: https://chromium-review.googlesource.com/c/crossbench/+/6660738
Reviewed-by: Camillo Bruni <[email protected]>
Commit-Queue: Kameron Lutes <[email protected]>

Author: kalutes

crossbench/cli/ui.py

@@ -70,9 +70,9 @@ def format_duration(duration: dt.timedelta) -> str:
 
   formatted = f"{round(seconds, 1)}s"
   if minutes:
-    formatted = "{minutes}m{formatted}"
+    formatted = f"{minutes}m{formatted}"
   if hours:
-    formatted = "{hours}h{formatted}"
+    formatted = f"{hours}h{formatted}"
   return formatted