docs: quick start example updated with fmt

Compiler Explorer finaly does not time out of fmt library :-)

README.md

@@ -55,6 +55,7 @@ the below example for a quick preview of basic library features:
 ```cpp
 #include <units/physical/si/speed.h>
 #include <units/physical/international/speed.h>
+#include <units/format.h>
 #include <iostream>
 
 using namespace units::physical;
@@ -73,10 +74,10 @@ int main()
   Speed auto v4 = quantity_cast<int>(v3);
 
   std::cout << v1 << '\n';                             // 110 km/h
-  std::cout << v2 << '\n';    // 70 mi/h
+  std::cout << fmt::format("{}", v2) << '\n';          // 70 mi/h
-  std::cout << v3 << '\n';    // 31.2928 m/s
+  std::cout << fmt::format("{:%Q in %q}", v3) << '\n'; // 31.2928 in m/s
-  std::cout << v4 << '\n';    // 31 m/s
+  std::cout << fmt::format("{:%Q}", v4) << '\n';       // 31
 }
 ```
 
-_Try it on the [Compiler Explorer](https://godbolt.org/z/f-f6y6)._
+_Try it on the [Compiler Explorer](https://godbolt.org/z/xE91TY)._

docs/quick_start.rst

@@ -33,6 +33,7 @@ of basic library features::
 
     #include <units/physical/si/speed.h>
     #include <units/physical/international/speed.h>
+    #include <units/format.h>
     #include <iostream>
 
     using namespace units::physical;
@@ -51,14 +52,14 @@ of basic library features::
       Speed auto v4 = quantity_cast<int>(v3);
 
       std::cout << v1 << '\n';                             // 110 km/h
-      std::cout << v2 << '\n';    // 70 mi/h
+      std::cout << fmt::format("{}", v2) << '\n';          // 70 mi/h
-      std::cout << v3 << '\n';    // 31.2928 m/s
+      std::cout << fmt::format("{:%Q in %q}", v3) << '\n'; // 31.2928 in m/s
-      std::cout << v4 << '\n';    // 31 m/s
+      std::cout << fmt::format("{:%Q}", v4) << '\n';       // 31
     }
 
 .. admonition:: Try it on Compiler Explorer
 
-    `Example #2 <https://godbolt.org/z/f-f6y6>`_
+    `Example #2 <https://godbolt.org/z/xE91TY>`_
 
 .. seealso::