DOC: added links to shardman and vops docs

Author: Liudmila Mantrova

doc/src/sgml/release-proee-10.sgml

@@ -17,7 +17,7 @@
           <filename>pg_shardman</filename>. This experimental extension
           enables sharding, aiming for scalability and fault tolerance
           with transaction support. It provides best results for
-          <acronym>OLTP</acronym> workloads.
+          <acronym>OLTP</acronym> workloads. (See <xref linkend="pg-shardman">.)
         </para>
       </listitem>
       <listitem>
@@ -31,7 +31,7 @@
         <para>
           <filename>vops</filename>. This extension enables vertical data model
           for &productname;. It can speed up <acronym>OLAP</acronym> queries
-          with filtering and aggregation by times.
+          with filtering and aggregation by times. (See <xref linkend="vops">.)
         </para>
       </listitem>
       <listitem>