user-manual: fix html
Add the missing closing tag for the h4 heading for bazelingore.
@@ -292,7 +292,7 @@ title: User Manual
Other files governing Bazel's behavior
</h3>
-<h4 id='.bazelignore'><code>.bazelignore</code>
+<h4 id='.bazelignore'><code>.bazelignore</code></h4>
<p>
You can specify directories within the workspace
that you want Bazel to ignore, such as related projects
