Fix inappropriate usage of "userPromptHandler" as capability name.

index.html

@@ -2132,7 +2132,7 @@ <h3>Processing capabilities</h3>
        used. The intent is that if this is not possible a new session
        will not be established.
 
-     <dt>"<code>userPromptHandler</code>"
+     <dt>"<code>unhandledPromptBehavior</code>"
      <dd><p>If <a>check user prompt handler matches</a>
      with <var>value</var> is false, return <a>success</a> with
      data <a><code>null</code></a>.
@@ -2295,18 +2295,18 @@ <h3>Global State</h3>
   "<code>acceptInsecureCerts</code>" from <var>capabilities</var>.
 
   <li><p>Let <var>user prompt handler capability</var> be the result of getting property
-  "<code>userPromptHandler</code>" from <var>capabilities</var>.
+  "<code>unhandledPromptBehavior</code>" from <var>capabilities</var>.
 
-   <li><p>If <var>user prompt handler capability</var> is not
+  <li><p>If <var>user prompt handler capability</var> is not
    undefined, <a>update the user prompt handler</a> with <var>user
    prompt handler capability</var>.
 
-   <li><p>Let <var>serialized user prompt handler</var>
+  <li><p>Let <var>serialized user prompt handler</var>
    be <a>serialize the user prompt handler</a>.
 
-   <li><p>If <var>seralized user prompt handler</var> is not null, set
+  <li><p>If <var>serialized user prompt handler</var> is not null, set
    a property on <var>capabilities</var> with the name
-   "<code>userPromptHandler</code>", and the value <var>serialized
+   "<code>unhandledPromptBehavior</code>", and the value <var>serialized
    user prompt handler</var>.
 
   <li><p>If <var>flags</var> <var>contains</var> "<code>http</code>":