Add docblocks for separator watcher prop

Author: mo3rfan

src/vue-numeric.vue

@@ -263,8 +263,13 @@ export default {
         })
       }
     },
-    
-    separator(newValue, oldValue) {
+
+    /**
+     * Immediately reflect separator changes
+     * @param {String} newValue
+     * @param {String} oldValue
+     */
+    separator (newValue, oldValue) {
         if (newValue !== oldValue) {
             this.process(this.valueNumber)
             this.amount = this.format(this.valueNumber)