docs: fixed some typos in the documentation (#9122)
docs: fixed some typos in the documentation (#9122)

Fixed some typos in the documentation for [html-generation.md](https://www.gatsbyjs.org/docs/html-generation/)
ChristopherBiscardi/gatsby,0x80/gatsby,ChristopherBiscardi/gatsby,gatsbyjs/gatsby,ChristopherBiscardi/gatsby,gatsbyjs/gatsby,mingaldrichgan/gatsby,gatsbyjs/gatsby,gatsbyjs/gatsby,0x80/gatsby,gatsbyjs/gatsby,mingaldrichgan/gatsby,ChristopherBiscardi/gatsby,gatsbyjs/gatsby,0x80/gatsby,mingaldrichgan/gatsby