message: Add custom cursors for macos
  The macos target now also supports the custom beam and underline
  cursors. The only thing left for this is now is testing and making sure
  it works with tiny fonts.
diff: @@ -461,6 +461,19 @@ impl Font {
  }
  pub fn get_glyph(&self, character: char, _size: f64, use_thin_strokes: bool) -> Result<RasterizedGlyph, Error> {
  + // Render custom symbols for underline and beam cursor
  + if character == super::UNDERLINE_CURSOR_CHAR {
  + let descent = -(self.ct_font.descent() as i32);
  + let width = self.glyph_advance('0') as i32;
  + return super::get_underline_cursor_glyph(descent, width);
  + } else if character == super::BEAM_CURSOR_CHAR {
  + let metrics = self.metrics();
  + let height = metrics.line_height;
  + let ascent = height - self.ct_font.descent() + 1.;
  + let width = self.glyph_advance('0') as i32;
  + return super::get_beam_cursor_glyph(ascent as i32, height as i32, width);
  + };
  +
  let glyph_index = self.glyph_index(character)
  .ok_or(Error::MissingGlyph(character))?;
  