doc: howto-man-page.txt: Use font macros instead of font escapes

doc: howto-man-page.txt: Use font macros instead of font escapes

  Use font macros instead of font escapes (\f[BIPR]).

  The escape '\c' ("connect to next input text")
is used to join the output of two macros without a space character.
This is similar to the '\' escape at the end of a line.

  Font escapes make the text more difficult to read.

###
  Changes based on:

  Use a macro to change to the italic font,
instead of \fI [1], if possible.
  The macros have the italic corrections,
but "\c" removes the "\/" part.

  Or

add the italic corrections.
[1] man-pages(7) [Debian package "manpages"]

###

Change a HYPHEN-MINUS (code 0x55, 2D) to a minus (\-), if in front of a

1) name for an option

2) negative number to be printed.

###

Wrong distance between sentences or protect the indicator.

a) Separate the sentences and subordinate clauses;
each begins on a new line.
See man-pages(7) [package "manpages"] and "info groff".

Or

b) Adjust space between sentences (two spaces),

c) or protect the indicator by adding "\&" after it.

The "indicator" is an "end-of-sentence character" (.!?).

  The amount of space between sentences in the output can then be
controlled with the ".ss" request.

Signed-off-by: Bjarni Ingi Gislason <bjarniig@rhi.hi.is>