Made SuggestionBox clear suggestions on escape (#2909)

webapp/components/suggestion/suggestion_box.jsx

@@ -110,6 +110,8 @@ export default class SuggestionBox extends React.Component {
             } else if (e.which === KeyCodes.ENTER || e.which === KeyCodes.TAB) {
                 GlobalActions.emitCompleteWordSuggestion(this.suggestionId);
                 e.preventDefault();
+            } else if (e.which === KeyCodes.ESCAPE) {
+                GlobalActions.emitClearSuggestions(this.suggestionId);
             } else if (this.props.onKeyDown) {
                 this.props.onKeyDown(e);
             }