[infra] use format strings instead of `.format`

Format strings are the convention in Py3

R=machenbach@chromium.org,alexschulze@chromium.org

Bug: chromium:1298869
Change-Id: Ia660e933f07d2a592c2edadaa99df68c47adb80d
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3521789
Auto-Submit: Tamer Tas <tmrts@chromium.org>
Reviewed-by: Michael Achenbach <machenbach@chromium.org>
Commit-Queue: Michael Achenbach <machenbach@chromium.org>
Cr-Commit-Position: refs/heads/main@{#79477}

PRESUBMIT.py

@@ -515,8 +515,7 @@ def _CheckNoexceptAnnotations(input_api, output_api):
                                    include_deletes=False):
     with open(f.LocalPath()) as fh:
       for match in re.finditer(regexp, fh.read()):
-        errors.append('in {}: {}'.format(f.LocalPath(),
-                                         match.group().strip()))
+        errors.append(f'in {f.LocalPath()}: {match.group().strip()}')
 
   if errors:
     return [output_api.PresubmitPromptOrNotify(