Remove now-unused entityclass::hormovingplatformfix()

This function is no longer used after I removed it in favor of using
`entityclass::moveblockto()`.

desktop_version/src/Entity.h

@@ -168,8 +168,6 @@ public:
 
     void movingplatformfix(int t, int j);
 
-    void hormovingplatformfix(int t);
-
     void entitycollisioncheck();
 
     void collisioncheck(int i, int j, bool scm = false);