Fix some errors in the documentation and other minor issues

[JohnoKing]

Somewhat notable changes in this pull request:

• The set +r bugfix (re: 74b4162) is now documented in the changelog.
• Missing options have been added to the synopsis section of the ksh man page.
• The minor formatting fix from fix a troff formatting error in the manpage. ksh-community/ksh#5 has been applied to the ksh man page.
• A few fixes from att/ast@5e747cfb have been applied to the ksh man page.
• The man page fixes from More sh.1 fixes and additions att/ast#353 have been applied, being:
  • An addition to document the behavior of set -H.
  • A fix for the cd section appending rksh93.
  • A fix for some options being indented too far.
  • Removal of a duplicate section documenting -D.
  • Reordering the options for set in alphabetical order.
  • A minor fix for the documentation of ksh -i.
• One minor fix from Red Hat has been applied to the ksh man page:
  https://git.centos.org/rpms/ksh/blob/c8/f/SOURCES/ksh-20120801-manfix4.patch

[McDutchie]

I think the Red Hat patch is wrong. This is what happens on my system:

$ ksh
$ echo $-
imsBE
$ sleep 30 &
[1]	36447
$ kill -s INT "$!"
[1] +                          sleep 30 &
$ kill -s INT "$!"
kill: 36447: no such process
$ set +o monitor
$ sleep 30 &
[1]	36448
$ kill -s INT "$!"
$ kill -s INT "$!"
$ kill -s QUIT "$!"
$ kill -s QUIT "$!"
$ 

I think that shows that SIGINT and SIGQUIT are indeed ignored when the -m/-o monitor option is not active, as the original text says.

[JohnoKing]

Red Hat's patch has been reverted. rhbz#1100215 and rhbz#1019334 may be worth looking into due to their connection to that patch.

Edit: The force-push has now updated the pull request.