Fix sharp corners for rectangles with StrokeKind != Inside (#5675)

Oops!

crates/egui_demo_lib/src/demo/tests/tessellation_test.rs

@@ -93,6 +93,19 @@ impl TessellationTest {
                 )
                 .with_blur_width(5.0),
             ),
+            (
+                "Additive rectangle",
+                RectShape::new(
+                    sized([24.0, 12.0]),
+                    0.0,
+                    egui::Color32::LIGHT_RED.additive().linear_multiply(0.025),
+                    (
+                        1.0,
+                        egui::Color32::LIGHT_BLUE.additive().linear_multiply(0.1),
+                    ),
+                    StrokeKind::Outside,
+                ),
+            ),
         ];
 
         for (_name, shape) in &mut shapes {

crates/egui_demo_lib/tests/snapshots/rendering_test/dpi_1.00.png

@@ -1,3 +1,3 @@
 version https://git-lfs.github.com/spec/v1
-oid sha256:9c6ce16a8a8c34d882485da6bbe08039fb55f90636da8136f68b1bb9baf0effb
-size 557610
+oid sha256:c03f90098fb2b2ff846586cc608126580050303b48e7c918b135efcdc6d52686
+size 554947

crates/egui_demo_lib/tests/snapshots/rendering_test/dpi_1.25.png

@@ -1,3 +1,3 @@
 version https://git-lfs.github.com/spec/v1
-oid sha256:a49c052578a46adb41bc02c6d7fdc264ed0ab8ae636cc8a11ac729fe1e48091b
-size 791802
+oid sha256:6ee96b64140d91e1b98cbf5dfef9ac5654050c48b3f9d36889f83a62c9ec985a
+size 788322

crates/egui_demo_lib/tests/snapshots/rendering_test/dpi_1.50.png

@@ -1,3 +1,3 @@
 version https://git-lfs.github.com/spec/v1
-oid sha256:989c55a83b8bc7cce4f459d8b835962377927a98f2bce085e92cba8438438ecd
-size 943736
+oid sha256:c82611e7b3ec5c7b82e552421aeef6ad5562d649339708ab6283e0c5af3589c6
+size 939339

crates/egui_demo_lib/tests/snapshots/rendering_test/dpi_1.67.png

@@ -1,3 +1,3 @@
 version https://git-lfs.github.com/spec/v1
-oid sha256:01ac61dc5bcecf6bf0d13c8399460b1afae652efe6fecc1d0e4b2f27d9f1c5a4
-size 1046906
+oid sha256:3b315e64464b060c4ef2b508bcb223663e0560871b82c9513fe232f92bd33609
+size 1041890

crates/egui_demo_lib/tests/snapshots/rendering_test/dpi_1.75.png

@@ -1,3 +1,3 @@
 version https://git-lfs.github.com/spec/v1
-oid sha256:3348923ecbad34e385e3ed52ab9b7c88b5d4fc07de00620302d5b191d90a453f
-size 1140236
+oid sha256:1dc4d7c51eb301ab3e0679b0247c96997ffa30b763c7b203a91fff706264d929
+size 1134943

crates/egui_demo_lib/tests/snapshots/rendering_test/dpi_2.00.png

@@ -1,3 +1,3 @@
 version https://git-lfs.github.com/spec/v1
-oid sha256:179c17b0405c6e87bd3cafaa7272e3e6d6eefd462b4406cca2a7abfe8af6f2bd
-size 1317569
+oid sha256:92c0615b09916c9a70fc898fbbde2921363044a3bcfcf82410e1d3f6e466bb8a
+size 1311678

crates/egui_demo_lib/tests/snapshots/tessellation_test/Additive rectangle.png

@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:70fd682bf6ba07b235cf2db643e9d050522aeb3e6ef28426c2b3d23c09920d22
+size 46196