c to cpp.

lib/web_ui/test/canvaskit/fragment_program_test.dart

@@ -185,7 +185,7 @@ const String kJsonIPLR = r'''
 ''';
 
 /// Generated by impellerc from
-/// ```c
+/// ```cpp
 /// #include <flutter/runtime_effect.glsl>
 /// uniform vec2 uSize;
 /// uniform float[10] uFloats;