Run gopls modernize on codebase (#34751)

Recent modernize fixes:
https://github.com/golang/tools/commits/master/gopls/internal/analysis/modernize

modules/avatar/identicon/block.go

@@ -24,8 +24,8 @@ func drawBlock(img *image.Paletted, x, y, size, angle int, points []int) {
 		rotate(points, m, m, angle)
 	}
 
-	for i := 0; i < size; i++ {
-		for j := 0; j < size; j++ {
+	for i := range size {
+		for j := range size {
 			if pointInPolygon(i, j, points) {
 				img.SetColorIndex(x+i, y+j, 1)
 			}

modules/avatar/identicon/identicon.go

@@ -134,7 +134,7 @@ func drawBlocks(p *image.Paletted, size int, c, b1, b2 blockFunc, b1Angle, b2Ang
 
 	// then we make it left-right mirror, so we didn't draw 3/6/9 before
 	for x := 0; x < size/2; x++ {
-		for y := 0; y < size; y++ {
+		for y := range size {
 			p.SetColorIndex(size-x, y, p.ColorIndexAt(x, y))
 		}
 	}