Avoid character.h import with forward declaraction

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Co-authored-by: Kevin Granade <[email protected]>

src/panels.h

@@ -8,14 +8,15 @@
 #include <string>
 #include <vector>
 
-#include "character.h"
 #include "color.h"
 #include "coordinates.h"
 #include "translations.h"
 
 class JsonIn;
 class JsonOut;
 class avatar;
+class Character;
+class Creature;
 struct point;
 
 // The display namespace contains UI string output and colorization functions