docs/156271: mergemaster(8) doesn't support -a and -i flags together

[linimon at FreeBSD.org]

Old Synopsis: mergemaster doesn't support -a and -i flags together
New Synopsis: mergemaster(8) doesn't support -a and -i flags together

Responsible-Changed-From-To: freebsd-doc->dougb
Responsible-Changed-By: linimon
Responsible-Changed-When: Sat Apr 9 20:18:17 UTC 2011
Responsible-Changed-Why: 
Over to maintainer.

http://www.freebsd.org/cgi/query-pr.cgi?pr=156271