Update man(1) to list the different sections of the manual

Add each of the intro sections to the 'Also See' list

PR:		193460
Differential Revision:	D834
Approved by:	bcr (mentor)
Sponsored by:	ScaleEngine Inc.


git-svn-id: svn+ssh://svn.freebsd.org/base/head@272135 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f