ggh4x 0.2.5: Floppy Disk

This is a small release for future compatibility with ggplot2, along with some
minor improvements. Moreover, the life cycle of guides has been set to
'questioning' because they might be migrated to a new package using an upcoming
overhaul of the guide system. The guides won't be deprecated until alternatives
are available.

New features

• facet_grid2(), and by extension facet_nested() too, gains a render_empty
  argument that can leave panels without data blank (#69).
• Added the solo_line argument to nested facets (#90).
• force_panelsizes() gains a total_width and total_height argument to
  set the size of the total panel area.

Improvements

• Swapped inheritance of the nest_line in nested facets: it is now a line
  element that inherits from blank elements, and the theme default is a blank
  element. This makes it more responsive to the theme setting (#89).
• Anticipated compatibility with future ggplot2 > 3.4.2.
• stat_difference() is now more performant, particularly for larger data.
• stat_difference() no longer outputs a 0-level.
• stat_rle() now considers NAs as equivalent values, unlike base::rle().
• Curb back overzealous whitespace removal in facet_manual() (#106).
• scale_{x/y}_facet() now uses quosures instead of expressions (#101).