Fix wrong link for dispatch tick actions (#1913)

Signed-off-by: Euclid Ye <euclid.ye@huawei.com>

Author: yezhizhen

index.html

@@ -9236,7 +9236,7 @@ <h3>Dispatching actions</h3>
    <li><p>Let <var>source</var> be the result of <a>get an input
     source</a> given <var>input state</var> and <var>input id</var>.
 
-   <li><p>Assert: <a>source</a> is not undefined.
+   <li><p>Assert: <var>source</var> is not undefined.
 
    <li><p>Let <var>global key state</var> be the result of <a>get the
    global key state</a> with <var>input state</var>.