add number (#665)

Author: Intron7

docs/release-notes/0.15.1.md

@@ -15,7 +15,7 @@
 
 ```{rubric} Misc
 ```
-* Tidy `_check_gpu_X` return value on the canonicalizing branch {pr}`xxx` {smaller}`S Dicks`
+* Tidy `_check_gpu_X` return value on the canonicalizing branch {pr}`664` {smaller}`S Dicks`
 * ``adata.uns[key_added]["params"]["resolution"]`` is now stored as a scalar ``float`` when a single resolution
 is passed to ``tl.leiden`` and ``tl.louvain`` to match behaviour in Scanpy, and as a ``list`` when multiple
 resolutions are passed. Previously it was always stored as a list. {pr}`648`. {smaller}`J Pintar`