ggplot2 4.0.1

This is a smaller patch release focussed on fixing regressions from 4.0.0 and
polishing the recent features.

Bug fixes

• Fixed regression where geom_area() didn't draw panels with single groups
  when stat = "align" (@teunbrand, #6680)
• Fixed regression where position_stack(vjust) was ignored when there are
  only single groups (#6692)
• Fixed bug where NA handling in geom_path() was ignoring panels (@teunbrand, #6533)
• Fixed bug where stat_bin(boundary) was ignored (#6682).
• geom_text() and geom_label() accept expressions as the label aesthetic
  (@teunbrand, #6638)
• Fixed regression where draw_key_rect() stopped using fill colours
  (@mitchelloharawild, #6609).
• Fixed regression where scale_{x,y}_*() threw an error when an expression
  object is set to labels argument (@yutannihilation, #6617).
• Fixed regression where the first (unnamed) argument to colour/fill scales was
  not passed as the name argument (@teunbrand, #6623)
• Fixed issue where vectorised arrow()s caused errors in drawing the
  legend glyphs (@teunbrand, #6594)
• Fixed regression where NULL-aesthetics contributed to plot labels too
  insistently. Now they contribute only as fallback labels (@teunbrand, #6616)
• Fixed regression where empty arguments to colour/fill scale caused errors
  (@jmbarbone, #6710)
• Fixed axis misplacement in coor_radial() when labels are blank (@teunbrand, #6574)

Improvements

• Improved palette fallback mechanism in scales (@teunbrand, #6669).
• Allow stat in geom_hline, geom_vline, and geom_abline. (@sierrajohnson, #6559)
• stat_boxplot() treats width as an optional aesthetic (@Yunuuuu, #6575)
• The theme(panel.widths, panel.heights) setting attempts to preserve the
  plot's aspect ratio when only one of the two settings is given, and the plot
  has a single panel (@teunbrand, #6701).
• Logical values for the linetype aesthetic will be interpreted numerically,
  so that linetype = FALSE becomes 0/'blank' and linetype = TRUE becomes
  1/'solid' (@teunbrand, #6641)
• Out-of-bounds datapoints used as padding by stat_align() now get removed
  silently rather than verbosely (@teunbrand, #6667)