change(/wiki/datastructures): add TODO's

Author: Longor1996

content/wiki/datastructures/index.md

@@ -18,9 +18,15 @@ or the performance of world generation, *too* much.
 
 > **Note:** These techniques can often be combined.
 
+- Hashgrid
 - [Multi-Level Grids](/wiki/datastructures/multi-level-grid)
 - [Sparse Voxel Octree (SVO)](/wiki/datastructures/sparse-voxel-octree)
 
+{{ todo_notice(body="List more datastructures?") }}
+{{ todo_notice(body="Compare datastructures?") }}
+{{ todo_notice(body="Explain complexity trade-offs? Table/diagram?") }}
+{{ todo_notice(body="Top- and bottom-level acceleration structures?") }}
+
 ## References
 
 - [https://0fps.net/2012/01/14/an-analysis-of-minecraft-like-engines/](https://0fps.net/2012/01/14/an-analysis-of-minecraft-like-engines/)