Clarify prefix-paths variable. (#23309)
Clarify prefix-paths variable. (#23309)

The line (one line, two places) I'm editing was copied from a comment in #21627 without the surrounding context. This edit provides that context.

Co-authored-by: gatsbybot <313a651c59fdaade90d152972001707d94b0975c@gmail.com>
gatsbyjs/gatsby,gatsbyjs/gatsby,gatsbyjs/gatsby,gatsbyjs/gatsby,gatsbyjs/gatsby,gatsbyjs/gatsby