setterm: improve wording and formatting of the man page

The main changes are: showing the arguments of boolean options
as optional, improving the alphabetization, and restoring the
--half-bright option that went missing in 2011.

Signed-off-by: Benno Schulenberg <bensberg@justemail.net>
setterm: improve formatting and wording of usage text

Mainly: showing that the word color is a placeholder by writing
<color>, showing some numbers as optional, and message levels
and colors as not optional.

Signed-off-by: Benno Schulenberg <bensberg@justemail.net>
lslogins: improve wording and formatting of the man page

Some typos, spacing, line breaks, and missing optional arguments.

Signed-off-by: Benno Schulenberg <bensberg@justemail.net>
lslogins: improve the columns information

Some fixes for typos, whitespace and wordings.

Signed-off-by: Benno Schulenberg <bensberg@justemail.net>
findmnt: slightly improve wording and formatting in man page

Signed-off-by: Karel Zak <kzak@redhat.com>
findmnt: minimally improve wording of usage text

Also sort the options better and tweak whitespace.

Signed-off-by: Benno Schulenberg <bensberg@justemail.net>
umount: slightly improve the man page

Remove some stray words from option arguments.

Signed-off-by: Benno Schulenberg <bensberg@justemail.net>