Specify flag equivalency for -A in portlint(1).

PR:		245338
Submitted by:	kevans

portlint.1

@@ -71,7 +71,8 @@ Show the progress report for items that are being checked.
 .It Fl t
 Nit pick about use of spaces.
 .It Fl A
-Turn on all additional checks.
+Turn on all additional checks.  This is equivalent to
+.Fl abcmNt .
 .It Fl C
 Pedantic committer flag.  This is equivalent to
 .Fl abcmt .