Revert change to ALTER TABLESPACE summary.

When ALTER TABLESPACE MOVE ALL was changed to be ALTER TABLE ALL IN
TABLESPACE, the ALTER TABLESPACE summary should have been adjusted back
to its original definition.

Patch by Thom Brown (thanks!).

doc/src/sgml/ref/alter_tablespace.sgml

@@ -33,8 +33,7 @@ ALTER TABLESPACE <replaceable>name</replaceable> RESET ( <replaceable class="PAR
 
   <para>
    <command>ALTER TABLESPACE</command> can be used to change the definition of
-   a tablespace or to migrate objects in the current database between
-   tablespaces.
+   a tablespace.
   </para>
 
   <para>