v0.22.1 — auto-rotate counts drawn labels and anchors at the tick

Patch: discrete-axis auto-rotate (#162).

Fixed

• The crowded-discrete-axis auto-rotate heuristic (0.22) counted every
  break in breaks(), including entries a with_labels override blanks
  ("") to thin a crowded axis while keeping every discrete position —
  over-triggering 45°/90° rotation over labels that would fit flat. The
  crowding count and the label-width estimate now only consider the
  labels actually drawn, measured with render::text::text_width
  (#162).
• Rotated bottom-axis labels — whether rotated by the auto-rotate
  heuristic or by an explicit axis_text_x_angle — could overlap the
  panel: the layout reserved a blind constant height that didn't grow with
  the label's real rotated extent, and the rotation anchor itself was
  placed at a fixed small offset from the axis line regardless of how
  much was reserved, so a long enough label's far end swung right back
  over the panel. layout_built's reservation and draw_x_axis's
  rotation-anchor placement now both derive from the same measured,
  per-label rotated bounding boxes (render::text::rotated_label_rise_fall),
  for both auto-rotated and explicitly-angled labels, on bottom and top
  axes alike.
• Changed rendering: auto-rotated crowded discrete axes now use −45°
  (was +45° in 0.22.0), ggplot2's angle = 45, hjust = 1 look mirrored to
  this library's angle sign. Every rotated label, auto or explicit, is
  anchored so its near-axis end sits at its own tick, on bottom and top
  axes (render::text::rotated_anchor_frac). Crowded discrete axes
  therefore render differently from 0.22.0.