Update openconfig-extensions.yang: trailing whitespace

release/models/openconfig-extensions.yang

@@ -173,7 +173,7 @@ module openconfig-extensions {
       protocol message. When the annotation is specified in the context
       of a list of containers, the atomic property applies to the
       contents of each individual keyed entry in the list. For example,
-      say ipv4-entry list has two elements, prefix1 and prefix2, all 
+      say ipv4-entry list has two elements, prefix1 and prefix2, all
       the elements under the prefix1 subtree may be updated as a
       result of a next-hop group change while prefix2 subtree is not
       updated.