Merge pull request #82849 from KoBeWi/change_dir_to_parallel_universe

Clarify `change_dir()` and access scopes

doc/classes/DirAccess.xml

@@ -71,6 +71,7 @@
  <description>
  Changes the currently opened directory to the one passed as an argument. The argument can be relative to the current directory (e.g. [code]newdir[/code] or [code]../newdir[/code]), or an absolute path (e.g. [code]/tmp/newdir[/code] or [code]res://somedir/newdir[/code]).
  Returns one of the [enum Error] code constants ([constant OK] on success).
+ [b]Note:[/b] The new directory must be within the same scope, e.g. when you had opened a directory inside [code]res://[/code], you can't change it to [code]user://[/code] directory. If you need to open a directory in another access scope, use [method open] to create a new instance instead.
  </description>
  </method>
  <method name="copy">