fix: link to creator showcase on submit page (#9822)
fix: link to creator showcase on submit page (#9822)

Fixes broken link on the [Submit to Creator Showcase](https://www.gatsbyjs.org/docs/submit-to-creator-showcase/) page, just below the title.

Closes #9761 

gatsbyjs/gatsby,ChristopherBiscardi/gatsby,gatsbyjs/gatsby,ChristopherBiscardi/gatsby,0x80/gatsby,gatsbyjs/gatsby,gatsbyjs/gatsby,ChristopherBiscardi/gatsby,gatsbyjs/gatsby,0x80/gatsby,0x80/gatsby,ChristopherBiscardi/gatsby,gatsbyjs/gatsby