refactor: the Sonar remarks on the small fixes taken care of

- the log stops through a flag kept in a function, not a global one
- the messages are put together with std::format
- a vehicle dropped on a trainset in the launcher goes in once the
  trainset is drawn, so the vehicles are gone through with a plain loop
  again; the drop split into a new vehicle and a moved one
- the scenario that can't be opened is caught as the runtime error it
  is, a file name outside of the code page as the system error it is
- a track of an unknown type is left out through the pointer owning it
- the keyword of a track type written out by a function of its own
- the picked node forgotten with ranges::replace_if, the empty
  Forget_Node of the base renderer told why it is empty
- FileCased takes the path it works on

rendering/renderer.h

@@ -91,7 +91,9 @@ public:
     virtual auto Pick_Control() const -> TSubModel const * = 0;
     virtual auto Pick_Node() const -> scene::basic_node const * = 0;
     // a node deleted from the scene is no longer given as picked
-    virtual void Forget_Node( scene::basic_node const *Node ) {}
+    virtual void Forget_Node( scene::basic_node const * /*Node*/ ) {
+        // a renderer which keeps no node picked has none to forget
+    }
 
     virtual auto Mouse_Position() const -> glm::dvec3 = 0;
     virtual auto Mouse_Hit() const -> bool { return true; }