automatically tag .SH and .SS in man(7) terminal output
in the same way as it was done for .Sh and .Ss in mdoc(7)

Introduce the concept of nodes that are semantically transparent:
they are skipped when looking for previous or following high-level
macros. Examples include roff(7) .ft, .ll, and .ta, mdoc(7) .Sm
and .Tg, and man(7) .DT and .PD. Use this concept for a variety
of improved decisions in various validators and formatters.

While here,
* remove a few const qualifiers on struct arguments that caused trouble;
* get rid of some more Yoda notation in the vicinity;
* and apply some other stylistic improvements in the vicinity.

I found this class of issues while considering .Tg patches from kn@.

Finally, represent the man(7) .PP and .HP macros by the natural
choice, which is <p> HTML element. On top of the previous fill-mode
improvements, the key to making this possible is to automatically
close the <p> when required: before headers, subsequent paragraphs,
lists, indented blocks, synopsis blocks, tbl(7) blocks, and before
blocks using no-fill mode.

In man(7) documents, represent the .sp request by a blank line in
no-fill mode and in the same way as .PP in fill mode.

ignore blank lines in man(7) next line scope;
strange groff edge case behaviour found in multimedia/mjpegtools

Give man(7) section and subsection headers heanging indentation.
Reduces groff-mandoc differences in base by about 2.5% due to
various Perl manuals having long section titles.
Quirk found in argtable2(3).

more tests regarding empty header lines

Introduce the concept of nodes that are semantically transparent:
they are skipped when looking for previous or following high-level
macros. Examples include roff(7) .ft, .ll, and .ta, mdoc(7) .Sm
and .Tg, and man(7) .DT and .PD. Use this concept for a variety
of improved decisions in various validators and formatters.

While here,
* remove a few const qualifiers on struct arguments that caused trouble;
* get rid of some more Yoda notation in the vicinity;
* and apply some other stylistic improvements in the vicinity.

I found this class of issues while considering .Tg patches from kn@.

Finally, represent the man(7) .PP and .HP macros by the natural
choice, which is <p> HTML element. On top of the previous fill-mode
improvements, the key to making this possible is to automatically
close the <p> when required: before headers, subsequent paragraphs,
lists, indented blocks, synopsis blocks, tbl(7) blocks, and before
blocks using no-fill mode.

In man(7) documents, represent the .sp request by a blank line in
no-fill mode and in the same way as .PP in fill mode.

ignore blank lines in man(7) next line scope;
strange groff edge case behaviour found in multimedia/mjpegtools

Give man(7) section and subsection headers heanging indentation.
Reduces groff-mandoc differences in base by about 2.5% due to
various Perl manuals having long section titles.
Quirk found in argtable2(3).

more tests regarding empty header lines

Finally, represent the man(7) .PP and .HP macros by the natural
choice, which is <p> HTML element. On top of the previous fill-mode
improvements, the key to making this possible is to automatically
close the <p> when required: before headers, subsequent paragraphs,
lists, indented blocks, synopsis blocks, tbl(7) blocks, and before
blocks using no-fill mode.

In man(7) documents, represent the .sp request by a blank line in
no-fill mode and in the same way as .PP in fill mode.

ignore blank lines in man(7) next line scope;
strange groff edge case behaviour found in multimedia/mjpegtools

Give man(7) section and subsection headers heanging indentation.
Reduces groff-mandoc differences in base by about 2.5% due to
various Perl manuals having long section titles.
Quirk found in argtable2(3).

more tests regarding empty header lines

ignore blank lines in man(7) next line scope;
strange groff edge case behaviour found in multimedia/mjpegtools

Give man(7) section and subsection headers heanging indentation.
Reduces groff-mandoc differences in base by about 2.5% due to
various Perl manuals having long section titles.
Quirk found in argtable2(3).

more tests regarding empty header lines