docs: Add a note about the effect of `@export`. (#10560)

Add information on @export and RPC.

tutorials/networking/high_level_multiplayer.rst

@@ -205,6 +205,8 @@ To check whether the peer is server or client:
 
     Multiplayer.IsServer();
 
+.. _doc_high_level_multiplayer_rpcs:
+
 Remote procedure calls
 ----------------------
 

tutorials/scripting/gdscript/gdscript_exports.rst

@@ -5,8 +5,9 @@ GDScript exported properties
 
 In Godot, class members can be exported. This means their value gets saved along
 with the resource (such as the :ref:`scene <class_PackedScene>`) they're
-attached to. They will also be available for editing in the property editor.
-Exporting is done by using the ``@export`` annotation.
+attached to, and get transferred over when using :ref:`RPCs <doc_high_level_multiplayer_rpcs>`.
+They will also be available for editing in the property editor. Exporting is done by using
+the ``@export`` annotation.
 
 ::