[Doc] Document loading behavior with relative paths

(cherry picked from commit 2508c2e309)

doc/classes/ResourceLoader.xml

@@ -78,6 +78,7 @@
 				Returns an empty resource if no [ResourceFormatLoader] could handle the file.
 				GDScript has a simplified [method @GDScript.load] built-in method which can be used in most situations, leaving the use of [ResourceLoader] for more advanced scenarios.
 				[b]Note:[/b] If [member ProjectSettings.editor/export/convert_text_resources_to_binary] is [code]true[/code], [method @GDScript.load] will not be able to read converted files in an exported project. If you rely on run-time loading of files present within the PCK, set [member ProjectSettings.editor/export/convert_text_resources_to_binary] to [code]false[/code].
+				[b]Note:[/b] Relative paths will be prefixed with [code]"res://"[/code] before loading, to avoid unexpected results make sure your paths are absolute.
 			</description>
 		</method>
 		<method name="load_threaded_get">

modules/gdscript/doc_classes/@GDScript.xml

@@ -169,7 +169,7 @@
 				# Load a scene called "main" located in the root of the project directory and cache it in a variable.
 				var main = load("res://main.tscn") # main will contain a PackedScene resource.
 				[/codeblock]
-				[b]Important:[/b] The path must be absolute. A relative path will always return [code]null[/code].
+				[b]Important:[/b] Relative paths are [i]not[/i] relative to the script calling this method, instead it is prefixed with [code]"res://"[/code]. Loading from relative paths might not work as expected.
 				This function is a simplified version of [method ResourceLoader.load], which can be used for more advanced scenarios.
 				[b]Note:[/b] Files have to be imported into the engine first to load them using this function. If you want to load [Image]s at run-time, you may use [method Image.load]. If you want to import audio files, you can use the snippet described in [member AudioStreamMP3.data].
 				[b]Note:[/b] If [member ProjectSettings.editor/export/convert_text_resources_to_binary] is [code]true[/code], [method @GDScript.load] will not be able to read converted files in an exported project. If you rely on run-time loading of files present within the PCK, set [member ProjectSettings.editor/export/convert_text_resources_to_binary] to [code]false[/code].