giscus settings in `_config.yml` had al-folio repo specified by default.
many users kept these defaults in their own repos, which resulted in
getting comments from blog posts of different users posted to al-folio
discussions. this is undesirable, since users lose control over the
discussions in their blogs.
this PR solves the issue:
- first, we set `giscus.repo` to blank in `_config.yml`. if the field is
kept blank, when the website is built locally, the user will see a
warning saying that giscus comments are misconfigured.
- second, we add a step to the `deploy` workflow that writes repository
name to `giscus.repo` in `_config.yml`. that way, even if `giscus.repo`
field is left black or set to an incorrect repo, it gets correctly
populated at deployment time.
other small changes in this PR are small stylistic adjustments.
8893d483bc