text: Render caret using lines

This patch makes the caret be drawn using lines.
This ensures that the width of the caret is always 1px.

Additionally, it improves caret positioning, so that it's closer to FP.

core/src/display_object/edit_text.rs

@@ -1008,15 +1008,17 @@ impl<'gc> EditText<'gc> {
         height: Twips,
         color: Color,
     ) {
-        let cursor_width = Twips::from_pixels(1.0);
+        let mut caret = context.transform_stack.transform().matrix
-        let caret = context.transform_stack.transform().matrix
+            * Matrix::create_box_with_rotation(
-            * Matrix::create_box(
+                1.0,
-                cursor_width.to_pixels() as f32,
                 height.to_pixels() as f32,
-                x - cursor_width,
+                std::f32::consts::FRAC_PI_2,
+                x,
                 Twips::ZERO,
             );
-        context.commands.draw_rect(color, caret);
+        let pixel_snapping = EditTextPixelSnapping::new(context.stage.quality());
+        pixel_snapping.apply(&mut caret);
+        context.commands.draw_line(color, caret);
     }
 
     /// Attempts to bind this text field to a property of a display object.