pgsql: Update text of terminate: < * Allow administrators to safely

Log Message:
-----------
Update text of terminate:

< * Allow administrators to safely terminate individual sessions
<
<   Right now, SIGTERM will terminate a session, but it is treated as
<   though the postmaster has paniced and shared memory might not be
<   cleaned up properly.  A new signal is needed for safe termination
<   because backends must first do a query cancel, then exit once they
<   have run the query cancel cleanup routine.
<
> * Allow administrators to safely terminate individual sessions either
>   via an SQL function or SIGTERM

Modified Files:
--------------
    pgsql/doc:
        TODO (r1.1568 -> r1.1569)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/TODO.diff?r1=1.1568&r2=1.1569)
    pgsql/doc/src/FAQ:
        TODO.html (r1.75 -> r1.76)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/FAQ/TODO.html.diff?r1=1.75&r2=1.76)