text: Title: [BUG] `dash.get_relative_path()` docstring out of date
  Body: Docstrings for `dash.get_relative_path()` and `dash.strip_relative_path()` still refer to the `app` way of accessing those functions, which creates inconsistency in the docs:
  
  ![Screen Shot 2023-05-02 at 2 44 32 PM](https://user-images.githubusercontent.com/4672118/235759684-d386ad8c-cee1-48a4-ba6c-9b54fb442440.png)
  
  https://dash.plotly.com/reference#dash.get_relative_path