Add missing references to "show route in" in the cli-help and doc.

The feature of showing all prefixes inside the given one has been added
in v2.0.9 but not well documented. Fixing it by this update.

Text in doc and commit message added by commiter.

doc/bird.sgml

@@ -1113,14 +1113,16 @@ This argument can be omitted if there exists only a single instance.
 	Show the list of symbols defined in the configuration (names of
 	protocols, routing tables etc.).
 
-	<tag><label id="cli-show-route">show route [[for] <m/prefix/|<m/IP/] [table (<m/t/ | all)] [(import|export) table <m/p/.<m/c/] [filter <m/f/|where <m/c/] [(export|preexport|noexport) <m/p/] [protocol <m/p/] [(stats|count)] [<m/options/]</tag>
+	<tag><label id="cli-show-route">show route [[(for|in)] <m/prefix/|for <m/IP/] [table (<m/t/|all)] [(import|export) table <m/p/.<m/c/] [filter <m/f/|where <m/cond/] [(export|preexport|noexport) <m/p/] [protocol <m/p/] [(stats|count)] [<m/options/]</tag>
 	Show contents of specified routing tables, that is routes, their metrics
 	and (in case the <cf/all/ switch is given) all their attributes.
 
 	<p>You can specify a <m/prefix/ if you want to print routes for a
 	specific network. If you use <cf>for <m/prefix or IP/</cf>, you'll get
 	the entry which will be used for forwarding of packets to the given
-	destination. By default, all routes for each network are printed with
+	destination. Finally, if you use <cf>in <m/prefix/</cf>, you get all
+	prefixes covered by the given prefix.
+	By default, all routes for each network are printed with
 	the selected one at the top, unless <cf/primary/ is given in which case
 	only the selected route is shown.
 

nest/config.Y

@@ -632,7 +632,7 @@ CF_CLI(SHOW INTERFACES SUMMARY,,, [[Show summary of network interfaces]])
 { if_show_summary(); } ;
 
 CF_CLI_HELP(SHOW ROUTE, ..., [[Show routing table]])
-CF_CLI(SHOW ROUTE, r_args, [[[<prefix>|for <prefix>|for <ip>] [table <t>] [(import|export) table <p>.<c>] [filter <f>|where <cond>] [all] [primary] [filtered] [(export|preexport|noexport) <p>] [protocol <p>] [stats|count]]], [[Show routing table]])
+CF_CLI(SHOW ROUTE, r_args, [[[<prefix>|for <prefix>|for <ip>|in <prefix>] [table <t>] [(import|export) table <p>.<c>] [filter <f>|where <cond>] [all] [primary] [filtered] [(export|preexport|noexport) <p>] [protocol <p>] [stats|count]]], [[Show routing table]])
 { rt_show($3); } ;
 
 r_args: