bug#53408: guile site broken link

[Bug reports for GUILE, GNU's Ubiquitous Extension Language]

Hi !

The link for Greg Badros' Scheme Lecture Notes on the page
https://www.gnu.org/software/guile/learn/ is broken.

Seems that there's just a / missing :
https://courses.cs.washington.edu/courses/cse341/99su/lectures/scheme/
works.

Cheers,