fix: don't emit if the decoration is already destroyed

Author: aminya

lib/decoration.js

@@ -113,6 +113,9 @@ export default class Decoration {
    * @return {Disposable} a disposable to stop listening to the event
    */
   onDidChangeProperties(callback) {
+    if (this.destroyed) {
+      return
+    }
     return this.emitter.on("did-change-properties", callback)
   }
 
@@ -124,6 +127,9 @@ export default class Decoration {
    * @return {Disposable} a disposable to stop listening to the event
    */
   onDidDestroy(callback) {
+    if (this.destroyed) {
+      return
+    }
     return this.emitter.on("did-destroy", callback)
   }