Because that's what it is. No point updating the same content
twice in different files :P
The reason is, Gridsome needs GhostPage to exist so the page gets
a valid path, but doesn't actually use it because it loads
GhostPost first. We could technically leave GhostPage as an empty
file, but if the order changes someday and GhostPage starts
getting prioritised over GhostPost we'll be in a mess. Might as
well keep ourselves covered.
GhostPost and GhostPage are copies of each other: they
conditionally render depending on whether the path matches a post
or page. The reason for this workaround is that, otherwise, the
router would show a 404 for non-matching posts even when a
matching page existed, since they both lie under the same path.
