In the mail section we have very different indentations and formatting in
texts with sanitize, links and texts with interpolations. In my opinion it
helps a lot to have clearer indentations in these cases.
This may not be the best way to indent them, but at least I think it is
clearer than it was and at least relatively unified.
Using the `_html` suffix in an i18n key is the same as using `html_safe`
on it, which means that translation could potentially be used for XSS
attacks.
The name `safe_html_with_links` was confusing and could make you think
it takes care of making the HTML safe. So I've renamed it in a way that
makes it a bit more intuitive that it expects its input to be already
sanitized.
I've changed `text_with_links` as well so now the two method names
complement each other.
