fix comment

Author: greggman

src/webgpu/shader/execution/shader_io/fragment_builtins.spec.ts

@@ -1270,19 +1270,19 @@ g.test('inputs,sample_mask')
       |.................../
       |................../
       |................./
-    +-----+-----+-----+-----+  ---
-    | |...|.....|..../|     |   ^
-    | |...|.....|.../ |     |   |
-    +-----+-----+-----+-----+   |
+    +-|---+-----+-----+/----+  ---
+    | |...|.....|...../     |   ^
+    | |...|.....|..../|     |   |
+    +-|---+-----+---/-+-----+   |
     | |...|.....|../  |     |   |
     | |...|.....|./   |     |   |
-    +-----+-----+-----+-----+   texture / clip space
-    | |...|.....|     |     |   |
+    +-|---+-----+/----+-----+   texture / clip space
+    | |...|...../     |     |   |
     | |...|..../|     |     |   |
-    +-----+-----+-----+-----+   |
+    +-|---+---/-+-----+-----+   |
     | |...|../  |     |     |   |
     | |...|./   |     |     |   V
-    +-----+-----+-----+-----+  ---
+    +-|---+/----+-----+-----+  ---
       |.../
       |../
       |./