docs: add picture of layouts

Author: wazolab

README.md

@@ -179,9 +179,12 @@ const clusterLayer = new TeritorioCluster(id, sourceId, options)
 ##### unfoldedClusterRender
 The following rendering function are at your disposal:
 - `unfoldedClusterRenderCircle`: Renders an unfolded cluster in a circular shape.
+![Circle layout](public/circle-layout.png)
 - `unfoldedClusterRenderHexaGrid`: Renders an unfolded cluster in a hexagonal grid spiral.
+![Hexagonal layout](public/hexagonal-layout.png)
 - `unfoldedClusterRenderGrid`: Renders an unfolded cluster in a square grid.
-- `unfoldedClusterRenderSmart` (default): Renders an unfolded cluster in a smart shape based on the number of items.
+![Grid layout](public/grid-layout.png)
+- `unfoldedClusterRenderSmart` (default): Renders an unfolded cluster in a smart shape (between circle and hexagonal) based on the number of items.
 
 ## Events