Add functions to news item

Author: wch

NEWS.md

@@ -7,7 +7,7 @@ There are three headlining features in this release of Shiny. It is now possible
 
 ### New features
 
-* Implemented [#1668](https://github.com/rstudio/shiny/issues/1668): dynamic tabs: added four functions (`insertTab`, `removeTab`, `showTab` and `hideTab`) that allow you to do those actions for an existing tabsetPanel. ([#1794](https://github.com/rstudio/shiny/pull/1794))
+* Implemented [#1668](https://github.com/rstudio/shiny/issues/1668): dynamic tabs: added functions (`insertTab`, `appendTab`, `prependTab`, `removeTab`, `showTab` and `hideTab`) that allow you to do those actions for an existing `tabsetPanel`. ([#1794](https://github.com/rstudio/shiny/pull/1794))
 
 * Implemented [#1213](https://github.com/rstudio/shiny/issues/1213): Added a new function, `onStop()`, which can be used to register callback functions that are invoked when an application exits, or when a user session ends. (Multiple sessions can be connected to a single running Shiny application.) This is useful if you have finalization/clean-up code that should be run after the application exits. ([#1770](https://github.com/rstudio/shiny/pull/1770)