LibWeb: Make a handful of paintable leaf classes `final`

Userland/Libraries/LibWeb/Painting/PaintableBox.h

@@ -163,7 +163,7 @@ private:
     Optional<BorderRadiusCornerClipper> mutable m_overflow_corner_radius_clipper;
 };
 
-class PaintableWithLines : public PaintableBox {
+class PaintableWithLines final : public PaintableBox {
     JS_CELL(PaintableWithLines, PaintableBox);
 
 public:

Userland/Libraries/LibWeb/Painting/SVGGeometryPaintable.h

@@ -11,7 +11,7 @@
 
 namespace Web::Painting {
 
-class SVGGeometryPaintable : public SVGGraphicsPaintable {
+class SVGGeometryPaintable final : public SVGGraphicsPaintable {
     JS_CELL(SVGGeometryPaintable, SVGGraphicsPaintable);
 
 public:

Userland/Libraries/LibWeb/Painting/SVGSVGPaintable.h

@@ -11,7 +11,7 @@
 
 namespace Web::Painting {
 
-class SVGSVGPaintable : public PaintableBox {
+class SVGSVGPaintable final : public PaintableBox {
     JS_CELL(SVGSVGPaintable, PaintableBox);
 
 public:

Userland/Libraries/LibWeb/Painting/TextPaintable.h

@@ -10,7 +10,7 @@
 
 namespace Web::Painting {
 
-class TextPaintable : public Paintable {
+class TextPaintable final : public Paintable {
     JS_CELL(TextPaintable, Paintable);
 
 public: