kbcontrol.1+kbdmap.1: improve manual descriptions

Update the man page descriptions so that apropos {console,keyboard}
finds more relevant man pages.

MFC after: 3 days
Reviewed by: imp, emase
Pull Request: https://github.com/freebsd/freebsd-src/pull/1275

(cherry picked from commit 580dc180c7ebd84a4aee27938a5f4a62520ac5d9)