fix stepper url typo in nav

[codomposer]

Fix: Issue 456

Closes #444
Closes #355
Closes #329

Problem

The Stepper navigation link had a typo in the URL (stepp/ instead of stepper/), causing a 404 error when users clicked the link.

Solution

Corrected the URL from stepp/ to stepper/ to point to the correct documentation page.

Changes

Before:

href: '[https://coreui.io/react/docs/forms/stepp/'](https://coreui.io/react/docs/forms/stepp/'),