ADDED: ACTION_GROUP documentation

Author: nkh

documentation/mdbook_asciio/src/config/user_bindings/group_bindings.md

@@ -6,19 +6,19 @@ Bindings can be grouped so you can use multiple key presses (vim-like) to reach
 ```perl
 
 'group name' =>
-	{
-	SHORTCUTS => 'C00-x',
-	
-	'sub group name' => 
-		{
-		SHORTCUTS => 'C00-x',
-		
-		'binding in sub group' => ['C00-x', sub { print "you're in x/x/x\n" ; } ],  
-		} ,
-	
-	'binding 1' => ['000-1', sub { print "you're in x/1\n" ; } ],  
-	'binding 2' => ['000-2', sub { print "you're in x/2\n" ; } ],  
-	},
+    {
+    SHORTCUTS => 'C00-x',
+
+    'binding group' => ['C00-x', ACTION_GROUP('next_level') ] ,
+    'binding 1'     => ['000-1', sub { print "you're in x/1\n" ; } ],  
+    },
+
+'group_next_level' => # need to be prefixed with 'group_'
+    {
+    SHORTCUTS => 'C00-y', # can be accessed directly
+
+    'binding in sub group' => ['C00-x', sub { print "you're in x/x/x\n" ; } ],  
+    } ,
 
 ```