fix(docs): Remove superfluous `-- ` from `gatsby develop` cmd (#20281)
fix(docs): Remove superfluous `-- ` from `gatsby develop` cmd (#20281)

Command doesn't work as written: `gatsby develop -- --host:0.0.0.0`. Does work with extra `-- ` removed.
gatsbyjs/gatsby,gatsbyjs/gatsby,gatsbyjs/gatsby,gatsbyjs/gatsby,gatsbyjs/gatsby,gatsbyjs/gatsby