Go-To-Gitlab button doesn't link correctly to line number or commit range, similar to #294

Created by: vanesa

Steps to reproduce:

1. Open https://sourcegraph.com/gitlab.com/gitlab-org/gitlab-runner@fix/process-killing-bug/-/blob/.codeclimate.yml#L10 .
2. Click on the 'Open on GitLab' icon

Expected behavior:

Opens https://sourcegraph.com/gitlab.com/gitlab-org/gitlab-runner@fix/process-killing-bug/-/blob/.codeclimate.yml#L10 .

Actual behavior:

Opens https://sourcegraph.com/gitlab.com/gitlab-org/gitlab-runner@fix/process-killing-bug/-/blob/.codeclimate.yml, so doesn't link to the line.

With the commit range:

Steps to reproduce:

1. Open https://sourcegraph.com/gitlab.com/gitlab-org/gitlab-runner/-/compare/...process-killing-bug
2. Click on the 'Open on GitLab' icon

Expected behavior:

Opens https://gitlab.com/gitlab-org/gitlab-runner/compare/master...process-killing-bug

Actual behavior:

Opens https://gitlab.com/gitlab-org/gitlab-runner