Chore: declare focus method in form component types (#10221)

types/autocomplete.d.ts

@@ -50,4 +50,9 @@ export declare class ElAutocomplete extends ElementUIComponent {
 
   /** Whether show suggestions when input focus */
   triggerOnFocus: boolean
+
+  /**
+   * Focus the Input component
+   */
+  focus (): void
 }