LibWeb: Implement CanvasRenderingContext2D.transform

Author: https://github.com/Lubrsi
Commit: df7a83ac0e
Pull-request: https://github.com/SerenityOS/serenity/pull/13604

Userland/Libraries/LibWeb/HTML/CanvasRenderingContext2D.idl

@@ -55,4 +55,7 @@ interface CanvasRenderingContext2D {
     CanvasGradient createLinearGradient(double x0, double y0, double x1, double y1);
     CanvasGradient createConicGradient(double startAngle, double x, double y);
 
+    // FIXME: All these `double`s should be `unrestricted double`
+    undefined transform(double a, double b, double c, double d, double e, double f);
+
 };