The githost.log name was often confused with GitHost.io. Rename this to
git_json.log to make it clear it's coming from Git and that it's JSON
data.

Previously, we used brackets to denote the tier badges,
but this made Kramdown, the docs site Markdown renderer,
show many warnings when building the site. This is now
fixed by using parentheses instead of square brackets.

This was caused by [PREMIUM] looking like a link to
Kramdown, which couldn't find a URL there.

See:
- https://gitlab.com/gitlab-com/gitlab-docs/merge_requests/484
- https://gitlab.com/gitlab-org/gitlab-ce/issues/63800

Also adds and one linting rule
and makes project conform to it.

Also slight edit and spelling correction

Part of issue 57874

Part of issue 57874