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@.

1 files changed, 26 insertions, 0 deletions

diff --git a/regress/mdoc/Fl/spacing.out_ascii b/regress/mdoc/Fl/spacing.out_ascii
new file mode 100644
index 00000000..c96c3923
--- /dev/null
+++ b/regress/mdoc/Fl/spacing.out_ascii
@@ -0,0 +1,26 @@
+FL-SPACING(1)               General Commands Manual              FL-SPACING(1)
+
+NNAAMMEE
+     FFll--ssppaacciinngg - horizontal spacing after flag macros
+
+DDEESSCCRRIIPPTTIIOONN
+     with argument: --aa
+
+     no next node: -- suffix
+
+     transparent next node only: -- suffix
+
+     following text: -- text
+
+     text after transparent node on the same line: -- text
+
+     following macro on the same line: --_w_o_r_d
+
+     following macro on the next line: -- _w_o_r_d
+
+     following macro on the next line after transparent node on the same line:
+     -- _w_o_r_d
+
+     following macro after transparent node on the next line: -- _w_o_r_d
+
+OpenBSD                        February 27, 2020                       OpenBSD