tidyp: document autoreconf issues with a source tarball

Co-authored-by: Sandro <[e-mail]>

pkgs/development/libraries/tidyp/default.nix

···
   version = "1.04";
 
   src = fetchurl {
+    # downloads from a legacy GitHub download page from ~11 years ago
+    # project does not work with autoconf anymore and the configure script cannot be generated from the source download
     url = "https://github.com/downloads/petdance/tidyp/${pname}-${version}.tar.gz";
     sha256 = "0f5ky0ih4vap9c6j312jn73vn8m2bj69pl2yd3a5nmv35k9zmc10";
   };