fix(gatsby-source-filesystem): Improve the description (#28252)
fix(gatsby-source-filesystem): Improve the description (#28252)

Currently it's "Gatsby plugin which parses files within a directory for further parsing by other plugins" which is rather opaque and CS-y.

This PR changes it to better describe how someone would actually use it — "build websites with data from your local filesystem"
gatsbyjs/gatsby,gatsbyjs/gatsby,gatsbyjs/gatsby,gatsbyjs/gatsby,gatsbyjs/gatsby,gatsbyjs/gatsby