HAMLLint: Fix `UnnecessaryInterpolation` offences

app/views/admin/runners/index.html.haml

app/views/admin/runners/show.html.haml

app/views/admin/system_info/show.html.haml

app/views/admin/users/show.html.haml

app/views/ci/lints/show.html.haml

app/views/discussions/_parallel_diff_discussion.html.haml

app/views/doorkeeper/authorizations/new.html.haml

app/views/groups/group_members/index.html.haml

app/views/groups/issues.html.haml

app/views/groups/merge_requests.html.haml

app/views/groups/milestones/index.html.haml

app/views/import/fogbugz/new_user_map.html.haml

app/views/notify/_reassigned_issuable_email.html.haml

app/views/notify/repository_push_email.html.haml

app/views/profiles/accounts/show.html.haml

app/views/profiles/show.html.haml

app/views/projects/blob/_editor.html.haml

app/views/projects/blob/_upload.html.haml

app/views/projects/ci/builds/_build.html.haml

app/views/projects/compare/show.html.haml