Rename w_p_conceal to w_p_conc for consistency.
diff --git a/runtime/doc/mlang.txt b/runtime/doc/mlang.txt
index d7127da..d122521 100644
--- a/runtime/doc/mlang.txt
+++ b/runtime/doc/mlang.txt
@@ -58,8 +58,10 @@
 			The locale {name} must be a valid locale on your
 			system.  Some systems accept aliases like "en" or
 			"en_US", but some only accept the full specification
-			like "en_US.ISO_8859-1".
-			With the "messages" argument the language used for
+			like "en_US.ISO_8859-1".  On Unix systems you can use
+			the this command to see what locales are supported: >
+				:!locale -a
+<			With the "messages" argument the language used for
 			messages is set.  This can be different when you want,
 			for example, English messages while editing Japanese
 			text.  This sets $LC_MESSAGES.