Fix typo in commit_checklist.md

Bug: None
Change-Id: Ib6b20ddf9345217295db25f5dc3a229a399af6a2
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2809640
Reviewed-by: Toby Huang <[email protected]>
Commit-Queue: Toby Huang <[email protected]>
Cr-Commit-Position: refs/heads/master@{#870218}
diff --git a/docs/commit_checklist.md b/docs/commit_checklist.md
index 3380498..f65bd690 100644
--- a/docs/commit_checklist.md
+++ b/docs/commit_checklist.md
@@ -161,7 +161,7 @@
     good idea to run try jobs for each new patchset with significant changes.
 *   `-r <chromium_username>` will add reviewers.
 *   `-b <bug_number>` automatically populates the bug reference line of the
-    commit message. Use `-b None` is there is no relevant crbug.
+    commit message. Use `-b None` if there is no relevant crbug.
 *   `--edit-description` will let you update the commit message. Using square
     brackets in the commit message title, like [hashtag], will add a hashtag to
     your CL. This feature is useful for grouping related CLs together.