Update GDExtension docs

Author: FailSpy

doc/classes/GDExtension.xml

@@ -12,6 +12,12 @@
 		<link title="GDExtension example in C++">$DOCS_URL/tutorials/scripting/gdextension/gdextension_cpp_example.html</link>
 	</tutorials>
 	<methods>
+		<method name="get_loaded_extension_path">
+			<return type="String" />
+			<description>
+				Returns the GDExtension configuration resource that successfully loaded in. If the library is unloaded, returns an empty string.
+			</description>
+		</method>
 		<method name="get_minimum_library_initialization_level" qualifiers="const">
 			<return type="int" enum="GDExtension.InitializationLevel" />
 			<description>
@@ -24,6 +30,12 @@
 				Returns [code]true[/code] if this extension's library has been opened.
 			</description>
 		</method>
+		<method name="is_substituted">
+			<return type="bool" />
+			<description>
+				Returns [code]true[/code] if this extension has loaded a substitute config (see [method get_loaded_extension_path]).
+			</description>
+		</method>
 	</methods>
 	<constants>
 		<constant name="INITIALIZATION_LEVEL_CORE" value="0" enum="InitializationLevel">