Bug 27469: Improve link text when returning to booksellers page

Bug 27469: Improve link text when returning to booksellers page

This is to make the link more accessible for screen readers.
1. (Without patch) go to 'Acquisitions' and then 'Basket'
2. The link for the booksellers page should say 'Click here to go back
to booksellers page'
3. Add patch
4. The link should now just say 'Go back to booksellers page', i.e.
there is now no 'Click here'

Signed-off-by: Owen Leonard <oleonard@myacpl.org>
Signed-off-by: Katrin Fischer <katrin.fischer.83@web.de>
Signed-off-by: Marcel de Rooy <m.de.rooy@rijksmuseum.nl>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>