Any program (person), that produces man pages, should check the output
for defects by using (both groff and nroff)

[gn]roff -mandoc -t -ww -b -z -K utf8 <man page>

  The same goes for man pages that are used as an input.

  For a style guide use

  mandoc -T lint

-.-

  Any "autogenerator" should check its products with the above mentioned
'groff', 'mandoc', and additionally with 'nroff ...'.

  It should also check its input files for too long (> 80) lines.

  This is just a simple quality control measure.

  The "autogenerator" may have to be corrected to get a better man page,
the source file may, and any additional file may.

  Common defects:

  Not removing trailing spaces (in in- and output).
  The reason for these trailing spaces should be found and eliminated.

  "git" has a "tool" to point out whitespace,
see for example "git-apply(1)" and git-config(1)")

  Not beginning each input sentence on a new line.
Line length and patch size should thus be reduced.

  The script "reportbug" uses 'quoted-printable' encoding when a line is
longer than 1024 characters in an 'ascii' file.

  See man-pages(7), item "semantic newline".

-.-

The difference between the formatted output of the original and patched file
can be seen with:

  nroff -mandoc <file1> > <out1>
  nroff -mandoc <file2> > <out2>
  diff -d -u <out1> <out2>

and for groff, using

\"printf '%s\n%s\n' '.kern 0' '.ss 12 0' | groff -mandoc -Z - \"

instead of 'nroff -mandoc'

  Add the option '-t', if the file contains a table.

  Read the output from 'diff -d -u ...' with 'less -R' or similar.

-.-.

  If 'man' (man-db) is used to check the manual for warnings,
the following must be set:

  The option \"-warnings=w\"

  The environmental variable:

export MAN_KEEP_STDERR=yes (or any non-empty value)

  or

  (produce only warnings):

export MANROFFOPT=\"-ww -b -z\"

export MAN_KEEP_STDERR=yes (or any non-empty value)

-.-