Remove explicit default destructors (#157)

From CppCoreGuidelines:

Rule of Zero: C.20: If you can avoid defining default operations, do.
C.52: Use inheriting constructors to import constructors into a derived class that does not need further explicit initialization.
DRY forward and using declarations.
Miscellaneous:

Fix format.sh to output examples with normalised paths in sorted order.

Co-authored-by: ArthurSonzogni <sonzogniarthur@gmail.com>

src/ftxui/component/renderer.cpp

@@ -18,7 +18,6 @@ class RendererBase : public ComponentBase {
 
   // Constructor.
   RendererBase(std::function<Element()> render) : render_(std::move(render)) {}
-  ~RendererBase() override = default;
 
   // Component implementation.
   Element Render() override { return render_(); }