DOC: improved pg-wrapper description

Author: Liudmila Mantrova

doc/src/sgml/ref/pg-wrapper.sgml

@@ -37,10 +37,22 @@
  <para>
   <application>pg-wrapper</application> is a shell script provided in
   the <productname>&productname;</productname> distribution to manage
-  <productname>&productname;</productname> symbolic links and
+  <productname>&productname;</productname> symbolic links for the
+  provided programs and adjust the handling of
   <acronym>SQL</acronym> man pages on Linux systems.
-  This script is provided as part of the <filename>postgrespro-std-&majorversion;-client</filename>
-  package. Once this package is installed, you can find <application>pg-wrapper</application>
+  Since <productname>&productname;</productname> is installed into
+  <filename>/opt/pgpro/std-&majorversion;</filename>, this is required to make
+  client and server programs available in the standard system
+  <envar>PATH</envar> and find the new <acronym>SQL</acronym> man pages.
+  This setup is not performed automatically at installation time to avoid possible conflicts
+  with other <productname>PostgreSQL</productname>-based products
+  you may have installed, unless you have opted for using the
+  <filename>postgrespro-std-&majorversion;</filename> quick-install package.
+ </para>
+ <para>
+  <application>pg-wrapper</application> is provided as part of the
+  <filename>postgrespro-std-&majorversion;-client</filename> package.
+  Once this package is installed, you can find <application>pg-wrapper</application>
   in the <filename><replaceable>install-dir</replaceable>/bin</filename>
   directory, where <replaceable>install-dir</replaceable> is
   <filename>/opt/pgpro/std-&majorversion;</filename>.