bug#50561: Wrong link at the "further reading" section of doc.

Dorai Sitaram’s online Scheme tutorial, Teach Yourself Scheme in Fixnum Days, is no longer at the link as indicated by current guile doc. The new link is https://ds26gte.github.io/tyscheme/index.html Link to the wrong guile doc -> https://www.gnu.org/software/guile/manual/html_node/Further-Readi

bug#50562: Wrong link at the "further reading" section of doc.

Dorai Sitaram’s online Scheme tutorial, Teach Yourself Scheme in Fixnum Days, is no longer at the link as indicated by current guile doc. The new link is https://ds26gte.github.io/tyscheme/index.html Link to the wrong guile doc -> https://www.gnu.org/software/guile/manual/html_node/Further-Readin