[use-shortcuts] support multiple shortcut sets "hpi,user" for ex.

public/js/shortcut.js

@@ -126,7 +126,7 @@
                         backtrackAfterApplying = true;
                         strPart = '@';
                         let options = [], noteRTE = $(input).closest('[note-rte]');
-                        let scSets = noteRTE.attr('use-shortcuts') ? noteRTE.attr('use-shortcuts').split(',') : 'user'
+                        let scSets = noteRTE.attr('use-shortcuts') ? noteRTE.attr('use-shortcuts').split(',') : ['user']
                         for (let i = 0; i < scSets.length; i++) {
                             if(window[$.trim(scSets[i]) + 'Shortcuts']) {
                                 options = options.concat(window[$.trim(scSets[i]) + 'Shortcuts']);