Close angle brackets in description for :open pseudo-class (#3243)

I saw this in
#3238 (review)
but failed to actually apply it before merging.

Author: ddbeck

features/open-closed.yml

@@ -1,5 +1,5 @@
 name: ":open"
-description: The `:open` CSS pseudo-class matches elements that have open states, like `<details`, `<dialog>`, or `<select>`, based on their state.
+description: The `:open` CSS pseudo-class matches elements that have open states, like `<details>`, `<dialog>`, or `<select>`, based on their state.
 spec: https://drafts.csswg.org/selectors-4/#open-state
 group: selectors
 compat_features: