Make definition identifiers singular, and use automatic term pluralization.

Author: gkellogg

common/algorithm-terms.html

@@ -48,7 +48,7 @@
     as a stack with elements from the previous <a>processor state</a>
     copied into a new <a>processor state</a> when entering a new
     <a>JSON object</a>.</dd>
-  <dt><dfn data-lt="promises">promise</dfn></dt><dd>
+  <dt><dfn>promise</dfn></dt><dd>
     A <a data-cite="ECMASCRIPT#sec-promise-objects" class="externalDFN">promise</a> is an object that represents the eventual result of a single asynchronous operation.
     Promises are defined in [[ECMASCRIPT]].</dd>
   <dt><dfn>require all flag</dfn></dt><dd>