Add: store headers for most savegame chunks

When a header is added, the chunk changes from CH_ARRAY type to
CH_TABLE type.

src/saveload/strings_sl.cpp

@@ -130,7 +130,6 @@ static void Load_NAME()
 	}
 }
 
-/** Chunk handlers related to strings. */
 static const ChunkHandler name_chunk_handlers[] = {
 	{ 'NAME', nullptr, Load_NAME, nullptr, nullptr, CH_READONLY },
 };