chore: Update pull-request generator docs

Key: requeueAfterSeconds, should be under spec[n].generators, not spec.requeueAfterSeconds.

Author: gitbluf

docs/Generators-Pull-Request.md

@@ -28,6 +28,7 @@ metadata:
 spec:
   generators:
   - pullRequest:
+      requeueAfterSeconds: 1800
       github:
         # The GitHub organization or user.
         owner: myorg
@@ -42,7 +43,6 @@ spec:
         # Labels is used to filter the PRs that you want to target. (optional)
         labels:
         - preview
-  requeueAfterSeconds: 1800
   template:
   # ...
 ```