Fix baseline for text items

In the previous renderer the text, by default, is drawn at the top of the
bounding box. The default femtovg alignment is more like QPainter, but
that's not quite what we want here.

sixtyfps_runtime/rendering_backends/gl/lib.rs

@@ -535,6 +535,7 @@ impl ItemRenderer for GLItemRenderer {
         );
         paint.set_font(&[font.font_id]);
         paint.set_font_size(text.font_pixel_size(self.scale_factor()));
+        paint.set_text_baseline(femtovg::Baseline::Top);
 
         let text_str = sixtyfps_corelib::items::Text::FIELD_OFFSETS.text.apply_pin(text).get();