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/dom/border.cpp

@@ -22,7 +22,6 @@ class Border : public Node {
                 std::end(simple_border_charset)) {}
   Border(Elements children, Pixel pixel)
       : Node(std::move(children)), charset_pixel(10, pixel) {}
-  ~Border() override {}
 
   std::vector<Pixel> charset_pixel;
   std::vector<wchar_t> charset;