Refactor the 404 page (#11042) (#11046)

* Refactor the 404 page



* Apply suggestions from code review



---------




(cherry picked from commit 137731d)

Signed-off-by: Fanit Kolchina <[email protected]>
Signed-off-by: Nathan Bower <[email protected]>
Signed-off-by: github-actions[bot] <github-actions[bot]@users.noreply.github.com>
Co-authored-by: github-actions[bot] <github-actions[bot]@users.noreply.github.com>
Co-authored-by: Nathan Bower <[email protected]>

Author: 3 people

404.md

@@ -8,5 +8,10 @@ nav_exclude: true
 
 ## Oops, this isn't the page you're looking for. 
 
-Maybe our [home page](https://docs.opensearch.org/latest/) or one of the commonly visited pages below will help. If you need further support, please use the feedback feature on the right side of the screen to get in touch.
+Try searching in the search bar or go to the [home page](https://docs.opensearch.org/latest/).
 
+If you need more help:
+
+* Leave us feedback on the right-hand side of the screen.
+* Connect with us on [Slack](https://opensearch.org/slack.html).
+* Open an [issue](https://github.com/opensearch-project/documentation-website/issues/new/choose).