fix updateGutter markers loop

Because we use Map for this.markers and this.messages, we need to update this code which had remained untouched!

lib/editor/index.js

@@ -247,8 +247,13 @@ class Editor {
       name: 'linter-ui-default',
       priority,
     })
-    this.markers.forEach((marker, message) => {
-      this.decorateMarker(message, marker, 'gutter')
+    this.markers.forEach((markers: Array<BufferMarker>, key: string) => {
+      const message = this.messages.get(key)
+      if (message) {
+        for (const marker of markers) {
+          this.decorateMarker(message, marker, 'gutter')
+        }
+      }
     })
   }
   removeGutter() {