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/button.cpp

@@ -23,8 +23,6 @@ class ButtonBase : public ComponentBase {
              Ref<ButtonOption> option)
       : label_(label), on_click_(on_click), option_(std::move(option)) {}
 
-  ~ButtonBase() override = default;
-
   // Component implementation:
   Element Render() override {
     auto style = Focused() ? inverted : nothing;