MFC r154990, r180071, r180112, r180154:
MFC r154990, r180071, r180112, r180154:

- use the ".Pa" macro for path names
- markup fixes
- advise to use rc script to SIGHUP mountd
- add some missing words
- add information about possiblity of using /prefix network notation [1]

PR:		docs/124373 [1]
Obtained from:	NetBSD [1]

jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase