Fix 313c6c45aa: [Script] Return rail types as list instead of bitmask. (#14617)

This is more idiomatic for scripts, and avoids exposing internal representation.

src/script/api/script_rail.hpp

@@ -49,14 +49,6 @@ public:
 		RAILTYPE_INVALID  = ::INVALID_RAILTYPE, ///< Invalid RailType.
 	};
 
-	/**
-	 * A bitmap with all possible rail types.
-	 */
-	enum RailTypes : int64_t {
-		/* Note: these values represent part of the in-game RailTypes enum */
-		INVALID_RAILTYPES = INT64_MAX, ///< Invalid RailTypes.
-	};
-
 	/**
 	 * A bitmap with all possible rail tracks on a tile.
 	 */