fix(docs): Link to Gatsby swag store (#8959)
fix(docs): Link to Gatsby swag store (#8959)

added link to swag store to descriptive text under Details header. I had to Google to find the link, might be nice to have it right here.
mingaldrichgan/gatsby,gatsbyjs/gatsby,ChristopherBiscardi/gatsby,ChristopherBiscardi/gatsby,mingaldrichgan/gatsby,gatsbyjs/gatsby,gatsbyjs/gatsby,0x80/gatsby,gatsbyjs/gatsby,gatsbyjs/gatsby,ChristopherBiscardi/gatsby,0x80/gatsby,mingaldrichgan/gatsby,ChristopherBiscardi/gatsby,gatsbyjs/gatsby,0x80/gatsby