(chore): generate 0.12.1 release notes (#2046)

Author: ilan-gold

docs/release-notes/0.12.1.md

@@ -0,0 +1,10 @@
+(v0.12.1)=
+### 0.12.1 {small}`2025-07-23`
+
+### Bug fixes
+
+- Fix `chunks` argument for {func}`anndata.experimental.read_elem_lazy` so that it uses the on-disk chunking when possible, and allow users to pass this argument through to the reading of {class}`anndata.experimental.backed.Dataset2D` {user}`ilan-gold` ({pr}`2033`)
+
+### Performance
+
+- Improve integer indexing performance of `h5` 1d arrays that are opened via {func}`anndata.experimental.read_elem_lazy` {user}`ilan-gold` ({pr}`2035`)