Linkify term 'start URL'.

index.html

@@ -607,8 +607,8 @@ <h3>
         <aside class="note" title="Default scope">
           <p>
             The "default scope" (when [=manifest/scope=] member is missing,
-            empty, or failure) is the start URL, but with its filename, query,
-            and fragment removed.
+            empty, or failure) is the [=start URL=], but with its filename,
+            query, and fragment removed.
           </p>
         </aside>
         <p>
@@ -822,12 +822,12 @@ <h3>
           <p>
             Given the above, it is RECOMMENDED that, upon installation, or any
             time thereafter, a user agent allows the user to inspect and, if
-            necessary, modify the <a>start URL</a> of an application.
+            necessary, modify the [=start URL=] of an application.
           </p>
           <p>
-            Additionally, developers MUST NOT use the <a>start URL</a> to
-            include information that uniquely identifies a user (e.g.,
-            "?user=123" or "/user/123/", or "https://user123.foo.bar").
+            Additionally, developers MUST NOT use the [=start URL=] to include
+            information that uniquely identifies a user (e.g., "?user=123" or
+            "/user/123/", or "https://user123.foo.bar").
           </p>
         </section>
       </section>
@@ -839,7 +839,7 @@ <h3>
           The [=manifest's=] <code><dfn data-export="" data-dfn-for=
           "manifest">id</dfn></code> member is a <a>string</a> that represents
           the <dfn>identity</dfn> for the application. The [=identity=] takes
-          the form of a URL, which is same origin as the start URL.
+          the form of a URL, which is same origin as the [=start URL=].
         </p>
         <p>
           The [=identity=] is used by user agents to uniquely identify the