Add parse support for multiple requirements after where separated by and (#4298)

Follow on to #4275 that added `where` parse support.

---------

Co-authored-by: Josh L <josh11b@users.noreply.github.com>
Co-authored-by: Richard Smith <richard@metafoo.co.uk>

toolchain/check/handle_where.cpp

@@ -36,6 +36,11 @@ auto HandleParseNode(Context& context, Parse::RequirementImplsId node_id)
   return context.TODO(node_id, "HandleRequirementImpls");
 }
 
+auto HandleParseNode(Context& context, Parse::RequirementAndId node_id)
+    -> bool {
+  return context.TODO(node_id, "HandleRequirementAnd");
+}
+
 auto HandleParseNode(Context& context, Parse::WhereExprId node_id) -> bool {
   return context.TODO(node_id, "HandleWhereExpr");
 }