Be more clear about builtin prompt.

git-svn-id: svn://bind10.isc.org/svn/bind10/trunk@923 e5f2f494-b856-4b98-b285-d166d9295462

src/bin/bindctl/bindctl.1

@@ -28,11 +28,15 @@ If this connection is not established,
 will exit.
 .\" TODO: what if msgq is running but no BindCtl or Boss groups?
 .Pp
-The command-line prompt shows
+The
+.Nm
+prompt shows
 .Dq "\*[Gt] " .
 The prompt will also display the location if changed.
 The options are based on the module in use.
-The command-line usage is:
+The
+.Nm
+usage is:
 .Pp
 .Ic module Ic command Op Ar "param1 = value1" Op Ar ", param2 = value2"
 .Pp