Update rfcs/0009-custom-health-checks/README.md

Co-authored-by: Max Jonas Werner <[email protected]>
Signed-off-by: Matheus Pimenta <[email protected]>

rfcs/0009-custom-health-checks/README.md

@@ -237,7 +237,7 @@ the respective status of the first expression that evaluates to `true`. If none
 expressions evaluate to `true`, we consider the custom resource in progress.
 
 When the `Failed` expression is not specified the controller will keep evaluating the
-`Current` expression until it returns `true`, and will give up after the timeout is reached.
+`Current` expression until it returns `true`, and will give up after the timeout defined in the Kustomization's `spec.timeout` field is reached.
 Users will be encouraged to provide a `Failed` expression to avoid stalling the reconciliation
 loop until the timeout is reached.