s-s-d(8): Document the optional “:group|gid” argument for --chuid

debian/changelog

@@ -181,6 +181,7 @@ dpkg (1.16.1) UNRELEASED; urgency=low
     - Use minus signs and hyphens consistently in man pages.
     - Fix reference to /etc/dpkg/dselect.cfg.d instead of dpkg.cfg.d in
       dselect(1).
+    - Add missing optional group|gid --chuid argument in start-stop-daemon(8).
   * Refer to Sources and Packages files as part of a repository instead of
     as being of exclusive use or owned by APT, which has never been the case.
   * Unify somewhat dpkg-maintscript-helper --help output with other commands.

man/start-stop-daemon.8

@@ -175,7 +175,7 @@ Return exit status 0 instead of 1 if no actions are (would be) taken.
 .BR \-q ", " \-\-quiet
 Do not print informational messages; only display error messages.
 .TP
-.BR \-c ", " \-\-chuid " \fIusername\fR|\fIuid\fP"
+.BR \-c ", " \-\-chuid " \fIusername\fR|\fIuid\fP[\fB:\fP\fIgroup\fR|\fIgid\fP]"
 Change to this username/uid before starting the process. You can also
 specify a group by appending a
 .BR : ,