(chore): generate 0.12.6 release notes (#2206)

Author: ilan-gold

docs/release-notes/0.12.6.md

@@ -0,0 +1,6 @@
+(v0.12.6)=
+### 0.12.6 {small}`2025-11-06`
+
+#### Bug fixes
+
+- Attach {class}`h5py.File` object to {class}`~anndata.AnnData` at the `file` attribute returned from  {func}`~anndata.experimental.read_lazy` {user}`ilan-gold` ({pr}`2204`)