Refactor documentation about privileges to centralize the info.

Expand section 5.6 "Privileges" to include the full definition of
each privilege type, and an explanation of aclitem privilege displays,
along with some helpful summary tables.  Most of this material came
out of the GRANT reference page, although some of it is new.
Adjust a bunch of links that were pointing to GRANT to point to 5.6.

Fabien Coelho and Tom Lane, reviewed by Bradley DeJong

Discussion: https://postgr.es/m/alpine.DEB.2.21.1807311735200.20743@lancre

Author: tglsfdc

doc/src/sgml/catalogs.sgml

@@ -1973,10 +1973,7 @@ SCRAM-SHA-256$<replaceable>&lt;iteration count&gt;</replaceable>:<replaceable>&l
       <entry><type>aclitem[]</type></entry>
       <entry></entry>
       <entry>
-       Access privileges; see
-       <xref linkend="sql-grant"/> and
-       <xref linkend="sql-revoke"/>
-       for details
+       Access privileges; see <xref linkend="ddl-priv"/> for details
       </entry>
      </row>
 
@@ -2679,10 +2676,7 @@ SCRAM-SHA-256$<replaceable>&lt;iteration count&gt;</replaceable>:<replaceable>&l
       <entry><type>aclitem[]</type></entry>
       <entry></entry>
       <entry>
-       Access privileges; see
-       <xref linkend="sql-grant"/> and
-       <xref linkend="sql-revoke"/>
-       for details
+       Access privileges; see <xref linkend="ddl-priv"/> for details
       </entry>
      </row>
     </tbody>
@@ -3491,10 +3485,7 @@ SCRAM-SHA-256$<replaceable>&lt;iteration count&gt;</replaceable>:<replaceable>&l
       <entry><type>aclitem[]</type></entry>
       <entry></entry>
       <entry>
-       Access privileges; see
-       <xref linkend="sql-grant"/> and
-       <xref linkend="sql-revoke"/>
-       for details
+       Access privileges; see <xref linkend="ddl-priv"/> for details
       </entry>
      </row>
 
@@ -3587,10 +3578,7 @@ SCRAM-SHA-256$<replaceable>&lt;iteration count&gt;</replaceable>:<replaceable>&l
       <entry><type>aclitem[]</type></entry>
       <entry></entry>
       <entry>
-       Access privileges; see
-       <xref linkend="sql-grant"/> and
-       <xref linkend="sql-revoke"/>
-       for details
+       Access privileges; see <xref linkend="ddl-priv"/> for details
       </entry>
      </row>
 
@@ -4052,9 +4040,7 @@ SCRAM-SHA-256$<replaceable>&lt;iteration count&gt;</replaceable>:<replaceable>&l
       <entry></entry>
       <entry>
        The initial access privileges; see
-       <xref linkend="sql-grant"/> and
-       <xref linkend="sql-revoke"/>
-       for details
+       <xref linkend="ddl-priv"/> for details
       </entry>
      </row>
 
@@ -4179,10 +4165,7 @@ SCRAM-SHA-256$<replaceable>&lt;iteration count&gt;</replaceable>:<replaceable>&l
       <entry><type>aclitem[]</type></entry>
       <entry></entry>
       <entry>
-       Access privileges; see
-       <xref linkend="sql-grant"/> and
-       <xref linkend="sql-revoke"/>
-       for details
+       Access privileges; see <xref linkend="ddl-priv"/> for details
       </entry>
      </row>
     </tbody>
@@ -4319,10 +4302,7 @@ SCRAM-SHA-256$<replaceable>&lt;iteration count&gt;</replaceable>:<replaceable>&l
       <entry><type>aclitem[]</type></entry>
       <entry></entry>
       <entry>
-       Access privileges; see
-       <xref linkend="sql-grant"/> and
-       <xref linkend="sql-revoke"/>
-       for details
+       Access privileges; see <xref linkend="ddl-priv"/> for details
       </entry>
      </row>
 
@@ -4386,10 +4366,7 @@ SCRAM-SHA-256$<replaceable>&lt;iteration count&gt;</replaceable>:<replaceable>&l
       <entry><type>aclitem[]</type></entry>
       <entry></entry>
       <entry>
-       Access privileges; see
-       <xref linkend="sql-grant"/> and
-       <xref linkend="sql-revoke"/>
-       for details
+       Access privileges; see <xref linkend="ddl-priv"/> for details
       </entry>
      </row>
     </tbody>
@@ -5396,10 +5373,7 @@ SCRAM-SHA-256$<replaceable>&lt;iteration count&gt;</replaceable>:<replaceable>&l
       <entry><type>aclitem[]</type></entry>
       <entry></entry>
       <entry>
-       Access privileges; see
-       <xref linkend="sql-grant"/> and
-       <xref linkend="sql-revoke"/>
-       for details
+       Access privileges; see <xref linkend="ddl-priv"/> for details
       </entry>
      </row>
     </tbody>
@@ -6810,10 +6784,7 @@ SCRAM-SHA-256$<replaceable>&lt;iteration count&gt;</replaceable>:<replaceable>&l
       <entry><type>aclitem[]</type></entry>
       <entry></entry>
       <entry>
-       Access privileges; see
-       <xref linkend="sql-grant"/> and
-       <xref linkend="sql-revoke"/>
-       for details
+       Access privileges; see <xref linkend="ddl-priv"/> for details
       </entry>
      </row>
 
@@ -7923,10 +7894,7 @@ SCRAM-SHA-256$<replaceable>&lt;iteration count&gt;</replaceable>:<replaceable>&l
       <entry><type>aclitem[]</type></entry>
       <entry></entry>
       <entry>
-       Access privileges; see
-       <xref linkend="sql-grant"/> and
-       <xref linkend="sql-revoke"/>
-       for details
+       Access privileges; see <xref linkend="ddl-priv"/> for details
       </entry>
      </row>
     </tbody>