[queue.defn] Remove superfluous whitespaces (cplusplus#8401)

Author: Andreas-Krug

source/containers.tex

@@ -15668,7 +15668,7 @@
     using reference       = Container::reference;
     using const_reference = Container::const_reference;
     using size_type       = Container::size_type;
-    using container_type  =          Container;
+    using container_type  = Container;
 
   protected:
     Container c;