Update src/types/db.ts

clarify comment

Co-authored-by: David Mears <60350599+david-mears-2@users.noreply.github.com>

src/types/db.ts

@@ -1,4 +1,4 @@
-// Result row used by TileDatabase to return BLOB mbtile data encoding feature boundaries
+// Result row used by TileDatabase to return BLOB mbtile data encoding feature boundaries for a single tile.
 export interface TileDataResultRow {
     tile_data: object;
 }