Migrate `Nm' and `Pa' handling from mdoc_action.c into mdoc_validate.c.

Document that `Pa' is replaced by a tilde, just like `Mt'.

1 files changed, 3 insertions, 0 deletions

diff --git a/mdoc.7 b/mdoc.7
index ba6ac2f9..8f58cdd3 100644
--- a/mdoc.7
+++ b/mdoc.7
@@ -2308,6 +2308,9 @@ and
 .Sx \&Ux .
 .Ss \&Pa
 A file-system path.
+If an argument is not provided, the string
+.Dq \(ti
+is used as a default.
 .Pp
 Examples:
 .D1 \&.Pa /usr/bin/mandoc