docs: q.force_in(U) documentation added

docs/users_guide/framework_basics/text_output.md

@@ -73,8 +73,8 @@ associated with this quantity.
     before passing it to the text output:
 
     ```cpp
-    std::cout << v1.in(km / h) << '\n';          // 110 km/h
-    std::cout << value_cast<m / s>(v1) << '\n';  // 30.5556 m/s
+    std::cout << v1.in(km / h) << '\n';       // 110 km/h
+    std::cout << v1.force_in(m / s) << '\n';  // 30.5556 m/s
     ```