fix docs: use delay when using @job decorator (#2088)

* fix docs: use delay to enqueue and use declared in separate file

Signed-off-by: Mehdi Nassim KHODJA <18899702+naskio@users.noreply.github.com>

* fix docs: use delay only

Signed-off-by: Mehdi Nassim KHODJA <18899702+naskio@users.noreply.github.com>

---------

Signed-off-by: Mehdi Nassim KHODJA <18899702+naskio@users.noreply.github.com>

docs/docs/index.md

@@ -439,7 +439,7 @@ from rq.decorators import job
 def add(x, y):
     return x + y
 
-job = add.enqueue(3, 4)
+job = add.delay(3, 4)
 time.sleep(1)
 print(job.return_value())
 ```