doc: consolidate PostgreSQL 9.4 pg_rewind references

Anyone still using PostgreSQL 9.4 should re-examine their life choices
at this point, but as it is not yet de-supported by repmgr, consolidate
the references to it whenever pg_rewind is mentioned to a single
section.

doc/repmgr-node-rejoin.xml

@@ -73,16 +73,16 @@
       </varlistentry>
 
       <varlistentry>
-        <term><option>--force-rewind[=/path/to/pg_rewind]</option></term>
+        <term><option>--force-rewind</option></term>
         <listitem>
           <para>
             Execute <application>pg_rewind</application>.
           </para>
           <para>
-            It is only necessary to provide the <application>pg_rewind</application> path
+            See <xref linkend="repmgr-node-rejoin-pg-rewind"/> for more details on using
-            if using PostgreSQL 9.4, and <application>pg_rewind</application>
+            <application>pg_rewind</application>.
-            is not installed in the PostgreSQL <filename>bin</filename> directory.
           </para>
+
         </listitem>
       </varlistentry>
 
@@ -261,8 +261,6 @@
     <para>
       <command>repmgr node rejoin</command> can optionally use <command>pg_rewind</command> to re-integrate a
       node which has diverged from the rest of the cluster, typically a failed primary.
-      <command>pg_rewind</command> is available in PostgreSQL 9.5 and later as part of the core distribution,
-      and can be installed from external sources for PostgreSQL 9.4.
     </para>
     <note>
       <para>
@@ -382,6 +380,29 @@
     DETAIL: node 2 is now attached to node 3</programlisting>
       </para>
     </refsect2>
+
+    <refsect2 id="repmgr-node-rejoin-postgresql-94" xreflabel="pg_rewind and PostgreSQL 9.4">
+
+      <title><command>pg_rewind</command> and PostgreSQL 9.4</title>
+
+      <indexterm>
+        <primary>pg_rewind</primary>
+        <secondary>PostgreSQL 9.4</secondary>
+      </indexterm>
+
+      <para>
+        <application>pg_rewind</application> is available in PostgreSQL 9.5 and later as part of the core distribution.
+        Users of PostgreSQL 9.4 will need to manually install it; the source code is available here:
+        <ulink url="https://github.com/vmware/pg_rewind">https://github.com/vmware/pg_rewind</ulink>.
+        If the <application>pg_rewind</application>
+        binary is not installed in the PostgreSQL <filename>bin</filename> directory, provide
+        its full path  on the demotion candidate  with <option>--force-rewind</option>.
+      </para>
+      <para>
+        Note that building the 9.4 version of <application>pg_rewind</application> requires the PostgreSQL
+        source code.
+      </para>
+    </refsect2>
   </refsect1>
 
   <refsect1 id="repmgr-node-rejoin-caveats" xreflabel="Caveats">
@@ -475,7 +496,7 @@
   <refsect1>
     <title>See also</title>
     <para>
-     <xref linkend="repmgr-standby-follow"/>
+     <xref linkend="repmgr-standby-follow"/>, <xref linkend="repmgr-standby-switchover"/>
     </para>
   </refsect1>
 </refentry>

doc/repmgr-standby-switchover.xml

@@ -154,9 +154,12 @@
           <para>
             Use <application>pg_rewind</application> to reintegrate the old primary if necessary
             (and the prerequisites for using <application>pg_rewind</application> are met).
+          </para>
+          <para>
             If using PostgreSQL 9.4, and the <application>pg_rewind</application>
             binary is not installed in the PostgreSQL <filename>bin</filename> directory,
-            provide its full path. For more details see also <xref linkend="switchover-pg-rewind"/>.
+            provide its full path. For more details see also <xref linkend="switchover-pg-rewind"/>
+            and <xref linkend="repmgr-node-rejoin-pg-rewind"/>.
           </para>
         </listitem>
       </varlistentry>

doc/switchover.xml

@@ -242,21 +242,12 @@
       </simpara>
     </note>
     <para>
-      For more details on <application>pg_rewind</application>, see:
+      For more details on <application>pg_rewind</application>, see section <xref linkend="repmgr-node-rejoin-pg-rewind"/>
+      in the <link linkend="repmgr-node-rejoin"><command>repmgr node rejoin</command></link> documentation and
+      the PostgreSQL documentation at
       <ulink url="https://www.postgresql.org/docs/current/app-pgrewind.html">https://www.postgresql.org/docs/current/app-pgrewind.html</ulink>.
     </para>
-    <para>
+
-      <application>pg_rewind</application> has been part of the core PostgreSQL distribution since
-      version 9.5. Users of PostgreSQL 9.4 will need to manually install it; the source code is available here:
-      <ulink url="https://github.com/vmware/pg_rewind">https://github.com/vmware/pg_rewind</ulink>.
-      If the <application>pg_rewind</application>
-      binary is not installed in the PostgreSQL <filename>bin</filename> directory, provide
-      its full path  on the demotion candidate  with <option>--force-rewind</option>.
-    </para>
-    <para>
-      Note that building the 9.4 version of <application>pg_rewind</application> requires the PostgreSQL
-      source code.
-    </para>
   </sect2>