Fix errors in 4200 discussion and resolution

Author: jwakely

xml/issue4200.xml

@@ -19,6 +19,7 @@ The current defn of the `operation_state` concept is:
 template<class O>
   concept operation_state =
     derived_from<typename O::operation_state_concept, operation_state_t> &&
+    is_object_v<O> &&
     requires (O& o) {
       { start(o) } noexcept;
     };
@@ -47,7 +48,7 @@ template<class O>
     derived_from<typename O::operation_state_concept, operation_state_t> &&
     <del>is_object_v&lt;O&gt; &amp;&amp;</del>
     requires (O&amp; o) {
-      <del>{</del> start(o) <del>} noexcept;</del>
+      <del>{</del> start(o) <del>} noexcept</del>;
     };
 </code></pre></blockquote>
 </li>