Update NEWS.md

Author: cpsievert

NEWS.md

@@ -4,7 +4,7 @@
 
 * `textInput()`, `textAreaInput()`, `numericInput()` and `passwordInput()` all gain an `updateOn` option. `updateOn = "change"` is the default and previous behavior, where the input value updates immediately whenever the value changes. With `updateOn = "blur"`, the input value will update only when the text input loses focus or when the user presses Enter (or Cmd/Ctrl + Enter for `textAreaInput()`). (#4183)
 
-* The `callback` argument of Shiny.js' `InputBinding.subscribe()` method gains support for a value of `"event"`. This makes it possible for an input binding to use event priority when updating the value (i.e., send immediately and always resend, even if the value hasn't changed).
+* The `callback` argument of Shiny.js' `InputBinding.subscribe()` method gains support for a value of `"event"`. This makes it possible for an input binding to use event priority when updating the value (i.e., send immediately and always resend, even if the value hasn't changed). (#4211)
 
 ## Improvements