This way blind screen reader users will know which proposal they're
supporting. In a list of proposals, context might not be clear when a
link saying "Support" or "Support this proposal" is announced, but a
link saying "Support Create a monthly transport ticket" is less
ambiguous.
Just like we did with investments in commit de436e33a, we're keeping the
title attribute because when visiting a proposal page, the connection
between the "Support" link and the proposal is not as clear as it is in
the proposals index page, so it might not be clear what you're
supporting.
This way we can make the view code a bit easier to read.
We're also changing the order of the conditions a little bit so we only
check for the presence of a current user once.
To make sure we aren't breaking anything with these changes, we're
adding some tests. We're also replacing one system test checking content
with a component test, since component tests are much faster.
