Fix wrong description (#651)

Signed-off-by: Maurice-1235 <[email protected]>

Author: mini-1235

configuration/packages/configuring-bt-navigator.rst

@@ -159,7 +159,7 @@ Parameters
   ====== =========
 
   Description
-    Path to behavior tree XML description.
+    Robot base frame.
 
 :odom_topic: