Fix misspellings on docs.bazel.build

RELNOTES: None.
PiperOrigin-RevId: 222438226

site/docs/user-manual.html

diff --git a/site/docs/user-manual.html b/site/docs/user-manual.html
index de8f1ae..198ae4a 100644
--- a/site/docs/user-manual.html
+++ b/site/docs/user-manual.html
@@ -2551,7 +2551,7 @@
   regular expression
     <ul>
       <li><code id='flag--task_tree_threshold'>--task_tree_threshold</code> skip tasks with duration
-      less than threshhold, in milliseconds. Default is 50ms</li>
+      less than threshold, in milliseconds. Default is 50ms</li>
     </ul>
   </li>
 </ul>