Nit: Quick Start Guide - Broken link during user onboarding

[burakdede]

Repro

Fresh user onboarding with no apps

Expected

• Land on the right documentation (in this case quick onboarding page)

Actual

• 404

It seems like link changed but not updated

• current - https://docs.tower.dev/quick-start-guide
• correct - https://docs.tower.dev/docs/getting-started/quick-start