codeintel locations: fix URLs by using git blob as resource

Created by: mrnugget

This fixes inconsistent behaviour in our GitBlobLSIFData resolver that would cause the Locations being returned in the definitions/references/... having /tree/ as opposed to /blob/ in their URL.

tree is only meant to be used for directories and not files, though, which is why the produced URLs that include line ranges would be redirected by our web application.

So this changes the second parameter of gql.CreateFileInfo to correctly say that the locations are not directories, but files.

Test plan

• Adjusted and ran unit tests