add Commands interface

packages/core/src/commands/blur.ts

@@ -1,12 +1,18 @@
-import { Command } from '../types'
+import { Command, Commands } from '../types'
 
 /**
  * Removes focus from the editor.
  */
-export const blur = (): Command => ({ view }) => {
+export const blur: Commands['blur'] = () => ({ view }) => {
   const element = view.dom as HTMLElement
 
   element.blur()
 
   return true
 }
+
+declare module '@tiptap/core' {
+  interface Commands {
+    blur: () => Command,
+  }
+}