Improve FILES section of psql reference page.

Primarily, explain where to find the system-wide psqlrc file, per recent
gripe from John Sutton.  Do some general wordsmithing and improve the
markup, too.

Also adjust psqlrc.sample so its comments about file location are somewhat
trustworthy.  (Not sure why we bother with this file when it's empty,
but whatever.)

Back-patch to 9.2 where the startup file naming scheme was last changed.

doc/src/sgml/ref/psql-ref.sgml

@@ -3513,42 +3513,53 @@ PSQL_EDITOR_LINENUMBER_ARG='--line '
  <refsect1>
   <title>Files</title>
 
-  <itemizedlist>
+ <variablelist>
+  <varlistentry>
+   <term><filename>psqlrc</filename> and <filename>~/.psqlrc</filename></term>
    <listitem>
     <para>
-     Unless it is passed an <option>-X</option>
-     or <option>-c</option> option,
-     <application>psql</application> attempts to
-     read and execute commands from the system-wide
-     <filename>psqlrc</filename> file and the user's
-     <filename>~/.psqlrc</filename> file before starting up.
-     (On Windows, the user's startup file is named
-     <filename>%APPDATA%\postgresql\psqlrc.conf</filename>.)
-     See <filename><replaceable>PREFIX</>/share/psqlrc.sample</>
-     for information on setting up the system-wide file.  It could be used
-     to set up the client or the server to taste (using the <command>\set
-     </command> and <command>SET</command> commands).
+     Unless it is passed an <option>-X</option> or <option>-c</option> option,
+     <application>psql</application> attempts to read and execute commands
+     from the system-wide startup file (<filename>psqlrc</filename>) and then
+     the user's personal startup file (<filename>~/.psqlrc</filename>), after
+     connecting to the database but before accepting normal commands.
+     These files can be used to set up the client and/or the server to taste,
+     typically with <command>\set</command> and <command>SET</command>
+     commands.
     </para>
     <para>
-     The location of the user's <filename>~/.psqlrc</filename> file can
-     also be set explicitly via the <envar>PSQLRC</envar> environment
-     setting.
+     The system-wide startup file is named <filename>psqlrc</filename> and is
+     sought in the installation's <quote>system configuration</> directory,
+     which is most reliably identified by running <literal>pg_config
+     --sysconfdir</>.  By default this directory will be <filename>../etc/</>
+     relative to the directory containing
+     the <productname>PostgreSQL</productname> executables.  The name of this
+     directory can be set explicitly via the <envar>PGSYSCONFDIR</envar>
+     environment variable.
+    </para>
+    <para>
+     The user's personal startup file is named <filename>.psqlrc</filename>
+     and is sought in the invoking user's home directory.  On Windows, which
+     lacks such a concept, the personal startup file is named
+     <filename>%APPDATA%\postgresql\psqlrc.conf</filename>.
+     The location of the user's startup file can be set explicitly via
+     the <envar>PSQLRC</envar> environment variable.
     </para>
-   </listitem>
-
-   <listitem>
     <para>
-     Both the system-wide <filename>psqlrc</filename> file and the user's
-     <filename>~/.psqlrc</filename> file can be made <application>psql</application>-version-specific
+     Both the system-wide startup file and the user's personal startup file
+     can be made <application>psql</application>-version-specific
      by appending a dash and the <productname>PostgreSQL</productname>
-     major or minor <application>psql</application> release number,
+     major or minor release number to the file name,
      for example <filename>~/.psqlrc-9.2</filename> or
      <filename>~/.psqlrc-9.2.5</filename>.  The most specific
      version-matching file will be read in preference to a
      non-version-specific file.
     </para>
    </listitem>
+  </varlistentry>
 
+  <varlistentry>
+   <term><filename>.psql_history</filename></term>
    <listitem>
     <para>
      The command-line history is stored in the file
@@ -3556,12 +3567,12 @@ PSQL_EDITOR_LINENUMBER_ARG='--line '
      <filename>%APPDATA%\postgresql\psql_history</filename> on Windows.
     </para>
     <para>
-     The location of the history file can
-     also be set explicitly via the <envar>PSQL_HISTORY</envar> environment
-     setting.
+     The location of the history file can be set explicitly via
+     the <envar>PSQL_HISTORY</envar> environment variable.
     </para>
    </listitem>
-  </itemizedlist>
+  </varlistentry>
+ </variablelist>
  </refsect1>
 
 

src/bin/psql/psqlrc.sample

 --
---	psql configuration file
+--	system-wide psql configuration file
 --
 --  This file is read before the .psqlrc file in the user's home directory.
 --
---  Copy this to your sysconf directory (typically /usr/local/pgsql/etc) and
---  rename it psqlrc.
+--  Copy this to your installation's sysconf directory and rename it psqlrc.
+--  The sysconf directory can be identified via "pg_config --sysconfdir".
+--