libman documents require `TH' and at least one node.

libman requirements documented in man.7 STRUCTURE section.
Added STRUCTURE section to mdoc.7, too.

1 files changed, 17 insertions, 1 deletions

diff --git a/mdoc.7 b/mdoc.7
index 52585e69..f27b31bc 100644
--- a/mdoc.7
+++ b/mdoc.7
@@ -278,7 +278,23 @@ In-lines have \(>=0 scoped arguments.
 
 \&.Yy \(lB\-arg \(lBval...\(rB\(rB arg0 arg1 argN
 .Ed
-.\"
+.\" SECTION
+.Sh STRUCTURE
+Each
+.Nm
+document must begin with the document prologue, containing, in order, 
+.Sq \&.Dd ,
+.Sq \&.Dt ,
+and
+.Sq \&.Os .
+.Pp
+Following these, the document body must begin with the NAME section
+containing at least one 
+.Sq \&.Nm
+followed by a
+.Sq \&.Nd
+macro.
+.\" SECTION
 .Sh MACROS
 This section contains a complete list of all 
 .Nm