Rename CreateAsyncContextSnapshot (#143)

The name of the  `CreateAsyncContextSnapshot` AO is confusing, since it's defined in the same section as the `AsyncContextSnapshot` AO, but the latter returns a spec-internal snapshot/mapping, whereas the former returns an `AsyncContext.Snapshot` object.

This patch renames it to `CreateAsyncContextSnapshotObject` to make this difference clearer.

Co-authored-by: Chengzhong Wu <cwu631@bloomberg.net>

Author: andreubotella

spec.html

@@ -801,9 +801,9 @@ <h1>
         </emu-alg>
       </emu-clause>
 
-      <emu-clause id="sec-createasynccontextsnapshot" type="abstract operation">
+      <emu-clause id="sec-createasynccontextsnapshotobject" type="abstract operation">
         <h1>
-          CreateAsyncContextSnapshot (
+          CreateAsyncContextSnapshotObject (
             _snapshotMapping_: an Async Context Mapping
           ): either a normal completion containing an AsyncContext.Snapshot object or a throw completion
         </h1>