docs(browser-apis): fix replaceHydrateFunction JSDoc comment (#9701)
docs(browser-apis): fix replaceHydrateFunction JSDoc comment (#9701)

`replaceHydrateFunction` is not currently showing up in the [Gatsby Browser APIs](https://www.gatsbyjs.org/docs/browser-apis/) section of the documentation site. The entries there are generated based on the JSDoc comments in `packages/gatsby/src/utils/api-browser-docs.js`, and the comment for `replaceHydrateFunction` was missing an asterisk, making it invalid JSDoc.
gatsbyjs/gatsby,ChristopherBiscardi/gatsby,ChristopherBiscardi/gatsby,0x80/gatsby,gatsbyjs/gatsby,gatsbyjs/gatsby,gatsbyjs/gatsby,gatsbyjs/gatsby,gatsbyjs/gatsby,0x80/gatsby,ChristopherBiscardi/gatsby,0x80/gatsby,ChristopherBiscardi/gatsby