bug#50554: Dead ada-mode link on the manuals webpage

[Alexandru-Sergiu Marton]

Hello,

I'd like to report a dead link on the manuals page. On
https://gnu.org/software/emacs/manual, the link for Ada-mode is leading
to a 404 page. I suspect this is because ada-mode was removed from the
standard GNU Emacs distribution in version 27, as I found this fragment
in etc/NEWS.27:

> ** ada-mode
> 
> *** The built-in ada-mode is now deleted.  The GNU ELPA package is a
> good replacement, even in very large source files.

Please sort this out whenever you have the time.

Thank you,
Alexandru-Sergiu Marton