docs: add hot.off to api-hmr document

docs/guide/api-hmr.md

@@ -37,6 +37,10 @@ interface ViteHotContext {
     event: T,
     cb: (payload: InferCustomEventPayload<T>) => void,
   ): void
+  off<T extends string>(
+    event: T,
+    cb: (payload: InferCustomEventPayload<T>) => void,
+  ): void
   send<T extends string>(event: T, data?: InferCustomEventPayload<T>): void
 }
 ```
@@ -181,6 +185,10 @@ The following HMR events are dispatched by Vite automatically:
 
 Custom HMR events can also be sent from plugins. See [handleHotUpdate](./api-plugin#handlehotupdate) for more details.
 
+## `hot.off(event, cb)`
+
+Remove callback from the event listeners
+
 ## `hot.send(event, data)`
 
 Send custom events back to Vite's dev server.