usr.bin/man: allow man(1) to search translated manpages in pure $man_lang subdirectory (+)

Currently our man(1) utility search manages only in $lang_country.$charset, $lang.$charset and,
as failover, in en.$charset which is historical behavior.
But nowadays most of ported software uses only $lang subdirectories for translated manpages
instead of use full locale notation, for example, share/ja/man1, share/de/man1, share/ru/man1.
In such cases, our man(1) utility cannot find any translated manpages and silently fallback to english version.

Add $man_lang in search path allows man(1) search and use translated manpages under historical and modern path traditions

MFC after:		1 day
MFC to:			stable/15 stable/14
Reviewed by:		ziaee, fernape
Approved by:		fernape
Differential Revision:	https://reviews.freebsd.org/D55805

(cherry picked from commit 5250c98908482babae8379b4dede10c64e8639ae)

2 files changed, 5 insertions, 1 deletions

diff --git a/usr.bin/man/man.1 b/usr.bin/man/man.1
index 707677ccce06..43c1d4c15056 100644
--- a/usr.bin/man/man.1
+++ b/usr.bin/man/man.1
@@ -225,6 +225,8 @@ will search for locale specific manual pages using the following logic:
 .It
 .Va lang . Ns Va charset
 .It
+.Va lang
+.It
 .Li en . Ns Va charset
 .El
 .Pp
@@ -242,6 +244,8 @@ will search the following paths when considering section 1 manual pages in
 .It
 .Pa /usr/share/man/ja.eucJP/man1
 .It
+.Pa /usr/share/man/ja/man1
+.It
 .Pa /usr/share/man/en.eucJP/man1
 .It
 .Pa /usr/share/man/man1
diff --git a/usr.bin/man/man.sh b/usr.bin/man/man.sh
index 920223ce3c27..f10209544ba7 100755
--- a/usr.bin/man/man.sh
+++ b/usr.bin/man/man.sh
@@ -748,7 +748,7 @@ man_setup_locale() {
 				man_country="${lang_cc#*_}"
 				man_charset="${locstr#*.}"
 				locpaths="$locstr"
-				locpaths="$locpaths:$man_lang.$man_charset"
+				locpaths="$locpaths:$man_lang.$man_charset:$man_lang"
 				if [ "$man_lang" != "en" ]; then
 					locpaths="$locpaths:en.$man_charset"
 				fi