doc: rename file endings from .sgml to .xml

As they are now XML files. In PostgreSQL itself they remain with
the .sgml suffix for backwards compatibility, but that's not
important for us.

doc/repmgr.xml

@@ -0,0 +1,134 @@
+<!-- doc/repmgr.xml -->
+
+<!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
+          "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd"
+[
+          <!ENTITY % version SYSTEM "version.xml">
+          %version;
+
+          <!ENTITY % filelist SYSTEM "filelist.xml">
+          %filelist;
+
+          <!ENTITY repmgr "<productname>repmgr</productname>">
+          <!ENTITY repmgrd "<productname>repmgrd</productname>">
+          <!ENTITY postgres "<productname>PostgreSQL</productname>">
+]>
+
+<book id="repmgr">
+ <title>repmgr &repmgrversion; Documentation</title>
+
+ <bookinfo>
+  <corpauthor>2ndQuadrant Ltd</corpauthor>
+  <productname>repmgr</productname>
+  <productnumber>&repmgrversion;</productnumber>
+  &legal;
+
+  <abstract>
+   <para>
+   This is the official documentation of &repmgr; &repmgrversion; for
+   use with PostgreSQL 9.3 - PostgreSQL 11.
+   </para>
+   <para>
+     &repmgr; is being continually developed and we strongly recommend using the
+     latest version. Please check the
+     <ulink url="https://repmgr.org/">repmgr website</ulink> for details
+     about the current &repmgr; version as well as the
+     <ulink url="https://repmgr.org/docs/current/index.html">current repmgr documentation</ulink>.
+   </para>
+
+   <para>
+    &repmgr; is developed by
+    <ulink url="https://2ndquadrant.com">2ndQuadrant</ulink>
+    along with contributions from other individuals and organisations.
+    Contributions from the community are appreciated and welcome - get
+    in touch via <ulink url="https://github.com/2ndQuadrant/repmgr">github</ulink>
+    or <ulink url="https://groups.google.com/group/repmgr">the mailing list/forum</ulink>.
+    Multiple 2ndQuadrant customers contribute funding
+    to make repmgr development possible.
+   </para>
+
+   <para>
+     &repmgr; is fully supported by 2ndQuadrant's
+     <ulink url="https://www.2ndquadrant.com/en/support/support-postgresql/">24/7 Production Support</ulink>.
+     2ndQuadrant, a Major Sponsor of the PostgreSQL project, continues to develop and maintain &repmgr;.
+     Other organisations as well as individual developers are welcome to participate in the efforts.
+   </para>
+  </abstract>
+
+  <keywordset>
+   <keyword>repmgr</keyword>
+   <keyword>PostgreSQL</keyword>
+   <keyword>replication</keyword>
+   <keyword>asynchronous</keyword>
+   <keyword>HA</keyword>
+   <keyword>high-availability</keyword>
+  </keywordset>
+ </bookinfo>
+
+
+ <part id="getting-started">
+  <title>Getting started</title>
+  &overview;
+  &install;
+  &quickstart;
+ </part>
+
+ <part id="repmgr-administration-manual">
+  <title>repmgr administration manual</title>
+
+  &configuration;
+  &cloning-standbys;
+  &promoting-standby;
+  &follow-new-primary;
+  &switchover;
+  &event-notifications;
+  &upgrading-repmgr;
+ </part>
+
+ <part id="using-repmgrd">
+  <title>Using repmgrd</title>
+  &repmgrd-overview;
+  &repmgrd-automatic-failover;
+  &repmgrd-configuration;
+  &repmgrd-operation;
+  &repmgrd-bdr;
+ </part>
+
+ <part id="repmgr-command-reference">
+  <title>repmgr command reference</title>
+
+  &repmgr-primary-register;
+  &repmgr-primary-unregister;
+  &repmgr-standby-clone;
+  &repmgr-standby-register;
+  &repmgr-standby-unregister;
+  &repmgr-standby-promote;
+  &repmgr-standby-follow;
+  &repmgr-standby-switchover;
+  &repmgr-witness-register;
+  &repmgr-witness-unregister;
+  &repmgr-node-status;
+  &repmgr-node-check;
+  &repmgr-node-rejoin;
+  &repmgr-node-service;
+  &repmgr-cluster-show;
+  &repmgr-cluster-matrix;
+  &repmgr-cluster-crosscheck;
+  &repmgr-cluster-event;
+  &repmgr-cluster-cleanup;
+  &repmgr-daemon-status;
+  &repmgr-daemon-start;
+  &repmgr-daemon-stop;
+  &repmgr-daemon-pause;
+  &repmgr-daemon-unpause;
+ </part>
+
+ &appendix-release-notes;
+ &appendix-signatures;
+ &appendix-faq;
+ &appendix-packages;
+ &appendix-support;
+
+ <index id="bookindex"></index>
+
+</book>