doc: Clarify pgstattuple privileges information

The description has gotten a bit confusing over time, so rewrite the
paragraph a bit.

Reported-by: Feike Steenbergen 

diff --git a/doc/src/sgml/pgstattuple.sgml b/doc/src/sgml/pgstattuple.sgml
index 611df9d0bfd0bc6d3e0863ecc998b4899e82448d..04a4423dc548bbc8e33cffbb75410b9b2d3c85a0 100644 (file)
--- a/doc/src/sgml/pgstattuple.sgml
+++ b/doc/src/sgml/pgstattuple.sgml
@@ -13,12 +13,14 @@
  
 
  
-  As these functions return detailed page-level information, only the superuser
-  has EXECUTE privileges on them upon installation.  After the functions have
-  been installed, users may issue GRANT commands to change
-  the privileges on the functions to allow non-superusers to execute them. Members
-  of the pg_stat_scan_tables role are granted access by default. See
-  the description of the  command for specifics.
+  Because these functions return detailed page-level information, access is
+  restricted by default.  By default, only the
+  role pg_stat_scan_tables has EXECUTE
+  privilege.  Superusers of course bypass this restriction.  After the
+  extension has been installed, users may issue GRANT
+  commands to change the privileges on the functions to allow others to
+  execute them.  However, it might be preferable to add those users to
+  the pg_stat_scan_tables role instead.