ci: include hugr-persistent in change detector (#2417)

https://github.com/CQCL/hugr/actions/runs/16067472898/job/45344608251
shows the check step not running, this should prevent that.

Driveby small change to a doc.

Author: acl-cqc

.github/change-filters.yml

@@ -24,6 +24,7 @@ rust: &rust
   - "hugr-cli/**"
   - "hugr-core/**"
   - "hugr-passes/**"
+  - "hugr-persistent/**"
   - "specification/schema/**"
 
 std-extensions:

hugr-persistent/src/wire.rs

@@ -15,9 +15,8 @@ pub struct PersistentWire {
 
 /// A wire within a commit HUGR of a [`PersistentHugr`].
 ///
-/// This is a `Wire` valid in a commit HUGR of a [`PersistentHugr`], along with
-/// the ID of the commit that contains the wire; this is equivalent to storing a
-/// wire of type `Wire<PatchNode>`.
+/// Also stores the ID of the commit that contains the wire;
+/// equivalent to (indeed contains) a `Wire<PatchNode>`.
 ///
 /// Note that it does not correspond to a valid wire in a [`PersistentHugr`]
 /// (see [`PersistentWire`]): some of its connected ports may be on deleted or