This allows us to use different "Show password" and "Hide password"
for these labels, which is more consistent with how other products
implement this.
It also lets us delete N duplicate copies of these strings in the HTML.
We fixed the main issue of this form in CVE-2020-9444, but the audit
done at that time only included links found in rendered_markdown; this
change completes our audit for links with target=_blank anywhere in
the codebase.