PR: www/159291

As remko@ assign this to me:
Implement a quick-and-dirty solution to fix a broken link on the Spanish
version of the website and link to the Spanish send-pr.html.

The Spanish version of the website has not seen an update since 2010
therefore most changes since then are either not available or are broken.

The send-pr web form is still working though. Tested with PR www/187222.