Just like we are already doing it in HTML output, automatically tag

section and subsection headers in terminal output, too.  Even though
admittedly, commands like "/SEE" and "/   Subsec" work, too, there
is no downside, and besides, with the recent improvements in the
tagging framework, implementation cost is negligible.

20 files changed, 85 insertions, 6 deletions

diff --git a/regress/mdoc/Cm/tag.out_tag b/regress/mdoc/Cm/tag.out_tag
index 0b97edbc..3a3a6b13 100644
--- a/regress/mdoc/Cm/tag.out_tag
+++ b/regress/mdoc/Cm/tag.out_tag
@@ -1,3 +1,5 @@
+NAME 3
+DESCRIPTION 6
 one 9
 two 9
 three 12
diff --git a/regress/mdoc/Dv/tag.out_tag b/regress/mdoc/Dv/tag.out_tag
index 94f0cfb2..848d769f 100644
--- a/regress/mdoc/Dv/tag.out_tag
+++ b/regress/mdoc/Dv/tag.out_tag
@@ -1,3 +1,5 @@
+NAME 3
+DESCRIPTION 6
 one 9
 two 9
 three 12
diff --git a/regress/mdoc/Em/tag.out_tag b/regress/mdoc/Em/tag.out_tag
index c2fbaf59..dd032f4f 100644
--- a/regress/mdoc/Em/tag.out_tag
+++ b/regress/mdoc/Em/tag.out_tag
@@ -1,3 +1,5 @@
+NAME 3
+DESCRIPTION 6
 one 9
 two 9
 three 12
diff --git a/regress/mdoc/Er/tag.out_tag b/regress/mdoc/Er/tag.out_tag
index b00a6718..c074e6cd 100644
--- a/regress/mdoc/Er/tag.out_tag
+++ b/regress/mdoc/Er/tag.out_tag
@@ -1,2 +1,5 @@
+NAME 3
+DESCRIPTION 6
 two 10
+ERRORS 12
 ENOENT 13
diff --git a/regress/mdoc/Ev/tag.out_tag b/regress/mdoc/Ev/tag.out_tag
index 94f0cfb2..848d769f 100644
--- a/regress/mdoc/Ev/tag.out_tag
+++ b/regress/mdoc/Ev/tag.out_tag
@@ -1,3 +1,5 @@
+NAME 3
+DESCRIPTION 6
 one 9
 two 9
 three 12
diff --git a/regress/mdoc/Fl/tag.out_tag b/regress/mdoc/Fl/tag.out_tag
index 89a94151..a3710cac 100644
--- a/regress/mdoc/Fl/tag.out_tag
+++ b/regress/mdoc/Fl/tag.out_tag
@@ -1,3 +1,5 @@
+NAME 3
+DESCRIPTION 6
 a 9
 b 9
 c 12
diff --git a/regress/mdoc/Fo/tag.out_tag b/regress/mdoc/Fo/tag.out_tag
index 2387023c..901861d1 100644
--- a/regress/mdoc/Fo/tag.out_tag
+++ b/regress/mdoc/Fo/tag.out_tag
@@ -1,3 +1,5 @@
+NAME 3
+DESCRIPTION 6
 first 9
 second 11
 e3 13
diff --git a/regress/mdoc/Ic/tag.out_tag b/regress/mdoc/Ic/tag.out_tag
index 94f0cfb2..848d769f 100644
--- a/regress/mdoc/Ic/tag.out_tag
+++ b/regress/mdoc/Ic/tag.out_tag
@@ -1,3 +1,5 @@
+NAME 3
+DESCRIPTION 6
 one 9
 two 9
 three 12
diff --git a/regress/mdoc/Li/tag.out_tag b/regress/mdoc/Li/tag.out_tag
index 94f0cfb2..848d769f 100644
--- a/regress/mdoc/Li/tag.out_tag
+++ b/regress/mdoc/Li/tag.out_tag
@@ -1,3 +1,5 @@
+NAME 3
+DESCRIPTION 6
 one 9
 two 9
 three 12
diff --git a/regress/mdoc/Ms/tag.out_tag b/regress/mdoc/Ms/tag.out_tag
index 94f0cfb2..848d769f 100644
--- a/regress/mdoc/Ms/tag.out_tag
+++ b/regress/mdoc/Ms/tag.out_tag
@@ -1,3 +1,5 @@
+NAME 3
+DESCRIPTION 6
 one 9
 two 9
 three 12
diff --git a/regress/mdoc/No/tag.out_tag b/regress/mdoc/No/tag.out_tag
index 94f0cfb2..848d769f 100644
--- a/regress/mdoc/No/tag.out_tag
+++ b/regress/mdoc/No/tag.out_tag
@@ -1,3 +1,5 @@
+NAME 3
+DESCRIPTION 6
 one 9
 two 9
 three 12
diff --git a/regress/mdoc/Sh/Makefile b/regress/mdoc/Sh/Makefile
index 4b37bb2a..ea21e502 100644
--- a/regress/mdoc/Sh/Makefile
+++ b/regress/mdoc/Sh/Makefile
@@ -1,11 +1,12 @@
-# $OpenBSD: Makefile,v 1.13 2020/02/27 21:38:27 schwarze Exp $
+# $OpenBSD: Makefile,v 1.14 2020/04/01 20:10:18 schwarze Exp $
 
 REGRESS_TARGETS	 = badNAME before empty emptyNAME first nohead order
 REGRESS_TARGETS	+= orderNAME paragraph parbefore parborder punctNAME
 REGRESS_TARGETS	+= subbefore tag transp
 LINT_TARGETS	 = badNAME before empty emptyNAME first nohead order
-LINT_TARGETS	+= orderNAME parbefore parborder punctNAME subbefore
+LINT_TARGETS	+= orderNAME parbefore parborder punctNAME subbefore tag
 HTML_TARGETS	 = paragraph tag
+TAG_TARGETS	 = tag
 
 # groff-1.22.3 defects:
 # - .Pp before .Sh NAME causes a blank line before the header line
diff --git a/regress/mdoc/Sh/tag.in b/regress/mdoc/Sh/tag.in
index 0e0e5fef..da8a884a 100644
--- a/regress/mdoc/Sh/tag.in
+++ b/regress/mdoc/Sh/tag.in
@@ -1,5 +1,5 @@
-.\" $OpenBSD: tag.in,v 1.1 2020/02/27 21:38:27 schwarze Exp $
-.Dd $Mdocdate: February 27 2020 $
+.\" $OpenBSD: tag.in,v 1.2 2020/04/01 20:10:18 schwarze Exp $
+.Dd $Mdocdate: April 1 2020 $
 .Dt SH-TAG 1
 .Os
 .Sh NAME
@@ -11,11 +11,17 @@ Text in the description.
 BEGINTEST
 .Pp
 Text in the subsection.
+.Sh DESCRIPTION
+Text in duplicate description section.
 .Tg examples
 .Sh EXAMPLES
 Text introducing examples.
 .Tg example
 .Ss Subsection
 Example text.
+.Sh "\&	 WEIRD SECTION	 "
+Text in weird section.
+.Sh \ \&
+Text in section with empty header.
 .Pp
 ENDTEST
diff --git a/regress/mdoc/Sh/tag.out_ascii b/regress/mdoc/Sh/tag.out_ascii
index df0ab050..309cb559 100644
--- a/regress/mdoc/Sh/tag.out_ascii
+++ b/regress/mdoc/Sh/tag.out_ascii
@@ -11,12 +11,21 @@ DDEESSCCRRIIPPTTIIOONN
 
      Text in the subsection.
 
+DDEESSCCRRIIPPTTIIOONN
+     Text in duplicate description section.
+
 EEXXAAMMPPLLEESS
      Text introducing examples.
 
    SSuubbsseeccttiioonn
      Example text.
 
+      WWEEIIRRDD SSEECCTTIIOONN
+     Text in weird section.
+
+
+     Text in section with empty header.
+
      ENDTEST
 
-OpenBSD                        February 27, 2020                       OpenBSD
+OpenBSD                          April 1, 2020                         OpenBSD
diff --git a/regress/mdoc/Sh/tag.out_html b/regress/mdoc/Sh/tag.out_html
index 9722aa8c..49c45fdb 100644
--- a/regress/mdoc/Sh/tag.out_html
+++ b/regress/mdoc/Sh/tag.out_html
@@ -2,8 +2,22 @@
 </section>
 </section>
 <section class="Sh">
+<h1 class="Sh" id="DESCRIPTION_2"><a class="permalink" href="#DESCRIPTION_2">DESCRIPTION</a></h1>
+<p class="Pp">Text in duplicate description section.</p>
+</section>
+<section class="Sh">
 <h1 class="Sh" id="examples"><a class="permalink" href="#examples">EXAMPLES</a></h1>
 <p class="Pp">Text introducing examples.</p>
 <section class="Ss">
 <h2 class="Ss" id="example"><a class="permalink" href="#example">Subsection</a></h2>
 <p class="Pp">Example text.</p>
+</section>
+</section>
+<section class="Sh">
+<h1 class="Sh" id="WEIRD_SECTION"><a class="permalink" href="#WEIRD_SECTION">	
+  WEIRD SECTION	 </a></h1>
+<p class="Pp">Text in weird section.</p>
+</section>
+<section class="Sh">
+<h1 class="Sh">&#x00A0;</h1>
+<p class="Pp">Text in section with empty header.</p>
diff --git a/regress/mdoc/Sh/tag.out_lint b/regress/mdoc/Sh/tag.out_lint
new file mode 100644
index 00000000..cfb1dfad
--- /dev/null
+++ b/regress/mdoc/Sh/tag.out_lint
@@ -0,0 +1,3 @@
+mandoc: tag.in:14:2: WARNING: duplicate section title: Sh DESCRIPTION
+mandoc: tag.in:22:7: WARNING: tab in filled text
+mandoc: tag.in:22:22: WARNING: tab in filled text
diff --git a/regress/mdoc/Sh/tag.out_markdown b/regress/mdoc/Sh/tag.out_markdown
index 2813f8f0..75a1e58e 100644
--- a/regress/mdoc/Sh/tag.out_markdown
+++ b/regress/mdoc/Sh/tag.out_markdown
@@ -14,6 +14,10 @@ BEGINTEST
 
 Text in the subsection.
 
+# DESCRIPTION
+
+Text in duplicate description section.
+
 # EXAMPLES
 
 Text introducing examples.
@@ -22,6 +26,14 @@ Text introducing examples.
 
 Example text.
 
+# 	 WEIRD SECTION	 
+
+Text in weird section.
+
+# &#160;
+
+Text in section with empty header.
+
 ENDTEST
 
-OpenBSD - February 27, 2020
+OpenBSD - April 1, 2020
diff --git a/regress/mdoc/Sh/tag.out_tag b/regress/mdoc/Sh/tag.out_tag
new file mode 100644
index 00000000..04b11882
--- /dev/null
+++ b/regress/mdoc/Sh/tag.out_tag
@@ -0,0 +1,7 @@
+NAME 3
+DESCRIPTION 6
+Subsection 9
+DESCRIPTION 14
+examples 17
+example 20
+WEIRD_SECTION 23
diff --git a/regress/mdoc/Sy/tag.out_tag b/regress/mdoc/Sy/tag.out_tag
index c2fbaf59..dd032f4f 100644
--- a/regress/mdoc/Sy/tag.out_tag
+++ b/regress/mdoc/Sy/tag.out_tag
@@ -1,3 +1,5 @@
+NAME 3
+DESCRIPTION 6
 one 9
 two 9
 three 12
diff --git a/regress/mdoc/Tg/warn.out_tag b/regress/mdoc/Tg/warn.out_tag
index e1fc141c..6426c3b5 100644
--- a/regress/mdoc/Tg/warn.out_tag
+++ b/regress/mdoc/Tg/warn.out_tag
@@ -1,3 +1,5 @@
+NAME 3
+DESCRIPTION 6
 start 9
 macro 9
 sub 9