Revision 364338

MFC r364131: tput(1): Several enhancements for the manual page

- a couple of descriptions are incomplete
- synopsis doesn't show that all arguments are optional
- missing an ENVIRONMENT section with TERM mentioned

PR:		84670
Submitted by:	Gary W. Swearingen <garys at opusnet dot com>
Reviewed by:	bcr
Approved by:	bcr
Differential Revision:	https://reviews.freebsd.org/D26009