Add documentation on the army type browser.

xtrn/war/docs/Rules

@@ -244,3 +244,12 @@ actions will be mailed to you in detail; also, you may receive mail from
 other national leaders this way.  To send Mail, press (S).  You may enter
 the name of the leader, or the word All to post a message in the News.
 
+
+Browsing Unit Types:
+
+The (A)rmy types display shows the names of all the army types available
+to all users in the game, their combat rating, their movement capabilites,
+and if they can transport other units.  When in the army type display,
+you may use (n)ext and (p)revious to view other pages or press ESC to
+return to the normal display.
+

xtrn/war/help.news

@@ -228,3 +228,12 @@ actions will be mailed to you in detail; also, you may receive mail from
 other national leaders this way.  To send Mail, press (S).  You may enter
 the name of the leader, or the word All to post a message in the News.
 
+
+ Browsing Unit Types
+
+The (A)rmy types display shows the names of all the army types available
+to all users in the game, their combat rating, their movement capabilites,
+and if they can transport other units.  When in the army type display,
+you may use (n)ext and (p)revious to view other pages or press ESC to
+return to the normal display.
+