Remove outdated comment

sparse_strips/vello_sparse_shaders/shaders/render_strips.wgsl

diff --git a/sparse_strips/vello_sparse_shaders/shaders/render_strips.wgsl b/sparse_strips/vello_sparse_shaders/shaders/render_strips.wgsl
index 843f1aa..fb0a7f3 100644
--- a/sparse_strips/vello_sparse_shaders/shaders/render_strips.wgsl
+++ b/sparse_strips/vello_sparse_shaders/shaders/render_strips.wgsl
@@ -411,7 +411,6 @@
             );
             
             // For sweep gradient, calculate angle from center using fast polynomial approximation
-            // Flip Y coordinate for screen coordinate system (Y increases downward)
             let unit_angle = xy_to_unit_angle(grad_pos.x, grad_pos.y);
             // Convert unit angle [0, 1) to radians [0, 2π)
             let angle = unit_angle * TWO_PI;