Represent mdoc(7) .Pp (and .sp, and some SYNOPSIS and .Rs features)

by the <p> HTML element and use the html_fillmode() mechanism
for .Bd -unfilled, just like it was done for man(7) earlier, finally
getting rid both of the horrible <div class="Pp"></div> hack and
of the worst HTML syntax violations caused by nested displays.

Care is needed because in some situations, paragraphs have to remain
open across several subsequent macros, whereas in other situations,
they must get closed together with a block containing them.

Some implementation details include:
* Always close paragraphs before emitting HTML flow content.
* Let html_close_paragraph() also close <pre> for extra safety.
* Drop the old, now unused function print_paragraph().
* Minor adjustments in the top-level man(7) node formatter for symmetry.
* Bugfix: .Ss heads suspend no-fill mode, even though .Ss doesn't end it.
* Bugfix: give up on .Op semantic markup for now, see the comment.

1 files changed, 23 insertions, 0 deletions

diff --git a/regress/mdoc/Rs/paragraph.out_ascii b/regress/mdoc/Rs/paragraph.out_ascii
new file mode 100644
index 00000000..821e721d
--- /dev/null
+++ b/regress/mdoc/Rs/paragraph.out_ascii
@@ -0,0 +1,23 @@
+RS-PARAGRAPH(1)             General Commands Manual            RS-PARAGRAPH(1)
+
+NNAAMMEE
+     RRss--ppaarraaggrraapphh - interaction of paragraphs and reference blocks
+
+DDEESSCCRRIIPPTTIIOONN
+     BEGINTEST
+     initial reference: author name, _b_o_o_k _t_i_t_l_e.
+
+     in a paragraph: another author, _a_n_o_t_h_e_r _b_o_o_k.
+
+SSEEEE AALLSSOO
+     initial reference:
+
+     author name, _b_o_o_k _t_i_t_l_e.
+
+     in a paragraph:
+
+     another author, _a_n_o_t_h_e_r _b_o_o_k.
+     ENDTEST
+     end of file
+
+OpenBSD                         January 7, 2019                        OpenBSD