Editorial: quick fixes re PR #1406

- Fix a 'use' production for AsyncConciseBody
  to match the new defining production.

- Add an <emu-prodref> for ExpressionBody to Annex A.

spec.html

@@ -21658,7 +21658,7 @@ <h1>Static Semantics: ContainsExpression</h1>
     <emu-clause id="sec-async-arrow-function-definitions-static-semantics-containsusestrict">
       <h1>Static Semantics: ContainsUseStrict</h1>
       <emu-see-also-para op="ContainsUseStrict"></emu-see-also-para>
-      <emu-grammar>AsyncConciseBody : AssignmentExpression</emu-grammar>
+      <emu-grammar>AsyncConciseBody : ExpressionBody</emu-grammar>
       <emu-alg>
         1. Return *false*.
       </emu-alg>
@@ -41674,6 +41674,7 @@ <h1>Functions and Classes</h1>
     <emu-prodref name=ArrowFunction></emu-prodref>
     <emu-prodref name=ArrowParameters></emu-prodref>
     <emu-prodref name=ConciseBody></emu-prodref>
+    <emu-prodref name=ExpressionBody></emu-prodref>
     <p>When the production <emu-prodref name=ArrowParameters a="parencover"></emu-prodref> is recognized the following grammar is used to refine the interpretation of |CoverParenthesizedExpressionAndArrowParameterList|:</p>
     <emu-prodref name=ArrowFormalParameters></emu-prodref>
     <p>&nbsp;</p>