Fix syntax error in layout_tests.md

Change-Id: Ibe8ccc0be09764fe4aca158dd9fec026bd7b4ce2
Reviewed-on: https://chromium-review.googlesource.com/592414
Reviewed-by: Quinten Yearsley <[email protected]>
Commit-Queue: Robert Ma <[email protected]>
Cr-Commit-Position: refs/heads/master@{#491435}
diff --git a/docs/testing/layout_tests.md b/docs/testing/layout_tests.md
index c8c8d25..9040fb3ad 100644
--- a/docs/testing/layout_tests.md
+++ b/docs/testing/layout_tests.md
@@ -220,7 +220,7 @@
   ```
 
   This will create new "virtual" tests of the form
-  `virtual/blocking_repaint/fast/repaint/...`` which correspond to the files
+  `virtual/blocking_repaint/fast/repaint/...` which correspond to the files
   under `LayoutTests/fast/repaint` and pass `--blocking-repaint` to
   content_shell when they are run.