docs(input,searchbar): setFocus usage within overlays (#27142)

<!-- Please refer to our contributing documentation for any questions on
submitting a pull request, or let us know here if you need any help:
https://ionicframework.com/docs/building/contributing -->

<!-- Some docs updates need to be made in the `ionic-docs` repo, in a
separate PR. See
https://github.com/ionic-team/ionic-framework/blob/main/.github/CONTRIBUTING.md#modifying-documentation
for details. -->

<!-- Please do not submit updates to dependencies unless it fixes an
issue. -->

<!-- Please try to limit your pull request to one type (bugfix, feature,
etc). Submit multiple pull requests if needed. -->

## What is the current behavior?
<!-- Please describe the current behavior that you are modifying. -->

The `setFocus` method does not mention extra implementation details
required when working within an overlay.

<!-- Issues are required for both bug fixes and features. -->
Issue URL: N/A


## What is the new behavior?
<!-- Please describe the behavior or changes that are being added by
this PR. -->

- Adds additional detail about how to use `setFocus()` when inside an
overlay
- Aligns the `ion-searchbar` documentation to match the `ion-input`
documentation

## Does this introduce a breaking change?

- [ ] Yes
- [x] No

<!-- If this introduces a breaking change, please describe the impact
and migration path for existing applications below. -->


## Other information

<!-- Any other information that is important to this PR such as
screenshots of how the component looks before and after the change. -->

core/src/components/input/input.tsx

@@ -397,6 +397,9 @@ export class Input implements ComponentInterface {
    *
    * Developers who wish to focus an input when a page enters
    * should call `setFocus()` in the `ionViewDidEnter()` lifecycle method.
+   *
+   * Developers who wish to focus an input when an overlay is presented
+   * should call `setFocus` after `didPresent` has resolved.
    */
   @Method()
   async setFocus() {