As mentioned in earlier commits, opening external links in a new
tab/window results in usability and accessibility issues.
Since these links are usually at the top or bottom of the page and
contain icons of well-known sites, IMHO there's no need to even notify
people that these are external links.
Since we're no longer using the `shared.target_blank` translation inside
a sentence, we can remove the space and parenthesis in the translations.
