Fix: reset roadtype/streetcartype info for non-road bridges

src/saveload/saveload.h

@@ -769,6 +769,19 @@ static inline bool IsSavegameVersionBefore(SaveLoadVersion major, byte minor = 0
 	return _sl_version < major || (minor > 0 && _sl_version == major && _sl_minor_version < minor);
 }
 
+/**
+ * Checks whether the savegame is below or at \a major. This should be used to repair data from existing
+ * savegames which is no longer corrupted in new savegames, but for which otherwise no savegame
+ * bump is required.
+ * @param major Major number of the version to check against.
+ * @return Savegame version is at most the specified version.
+ */
+static inline bool IsSavegameVersionUntil(SaveLoadVersion major)
+{
+	extern SaveLoadVersion _sl_version;
+	return _sl_version <= major;
+}
+
 /**
  * Checks if some version from/to combination falls within the range of the
  * active savegame version.