Update extensions.md (chartjs#4930)

Removed trailing space from waterfall-plugin.

docs/notes/extensions.md

@@ -18,7 +18,7 @@ In addition, many charts can be found on the [npm registry](https://www.npmjs.co
  - <a href="https://github.com/chartjs/chartjs-plugin-deferred" target="_blank">chartjs-plugin-deferred</a> - Defers initial chart update until chart scrolls into viewport.
  - <a href="https://github.com/compwright/chartjs-plugin-draggable" target="_blank">chartjs-plugin-draggable</a> - Makes select chart elements draggable with the mouse.
  - <a href="https://github.com/y-takey/chartjs-plugin-stacked100" target="_blank">chartjs-plugin-stacked100</a> - Draws 100% stacked bar chart.
-  - <a href="https://github.com/everestate/chartjs-plugin-waterfall" target="_blank">chartjs-plugin-waterfall</a> - Enables easy use of waterfall charts.
+ - <a href="https://github.com/everestate/chartjs-plugin-waterfall" target="_blank">chartjs-plugin-waterfall</a> - Enables easy use of waterfall charts.
  - <a href="https://github.com/chartjs/chartjs-plugin-zoom" target="_blank">chartjs-plugin-zoom</a> - Enables zooming and panning on charts.
 
 In addition, many plugins can be found on the [npm registry](https://www.npmjs.com/search?q=chartjs-plugin-).