level_resource changed to world_resource

Signed-off-by: Norbert Prokopiuk <norbert.prokopiuk@robotec.ai>

Author: norbertprokopiuk

srv/LoadWorld.srv

@@ -5,7 +5,7 @@
 # Currently loaded worlds will be unloaded before attempting to load a new one.
 # Any previously spawned entities will be removed. Once a world is loaded, simulation will be left in a Stopped state.
 
-Resource level_resource                     # Resource such as SDF, USD, MJCF, or other simulator-native format world file or,
+Resource world_resource                     # Resource such as SDF, USD, MJCF, or other simulator-native format world file or,
                                             # Simulation world passed as a string. 
 
 bool fail_on_unsupported_element            # Fail on unsupported elements (such as SDFormat sub-tags). By default, such elements are ignored.