doc pg_constraint.convalidated column description need update

hi.

catalog.sgml:

     <row>
      <entry role="catalog_table_entry"><para role="column_definition">
       <structfield>convalidated</structfield> <type>bool</type>
      </para>
      <para>
       Has the constraint been validated?
       Currently, can be false only for foreign keys and CHECK constraints
      </para></entry>
     </row>

with NOT NULL NOT VALID,
we need rephrase it to something like:
"Currently, can be false only for foreign keys, CHECK and not-null constraints"
I am also ok with just deleting it.


BTW, I happen to notice a minor issue:
some pg_catalog table column entry descriptions ending with a period,
some didn't.