treewide: Change URLs to HTTPS

Lots of URLs were HTTP redirect to HTTPS. Changed those and checked them
if there's actual content. Inspired by
https://github.com/NixOS/nixpkgs/issues/60004

doc/languages-frameworks/haskell.section.md

@@ -366,7 +366,7 @@ automatically select the right version of GHC and other build tools to build,
 test and execute apps in an existing project downloaded from somewhere on the
 Internet. Pass the `--nix` flag to any `stack` command to do so, e.g.
 ```shell
-git clone --recursive http://github.com/yesodweb/wai
+git clone --recursive https://github.com/yesodweb/wai
 cd wai
 stack --nix build
 ```

doc/languages-frameworks/python.section.md

@@ -445,7 +445,7 @@ buildPythonPackage rec {
   };
 
   meta = with lib; {
-    homepage = "http://github.com/pytoolz/toolz/";
+    homepage = "https://github.com/pytoolz/toolz/";
     description = "List processing tools and functional utilities";
     license = licenses.bsd3;
     maintainers = with maintainers; [ fridh ];

doc/languages-frameworks/vim.section.md

@@ -250,6 +250,6 @@ override to the `pkgs/misc/vim-plugins/default.nix` in the same directory.
 - [vim-pi](https://bitbucket.org/vimcommunity/vim-pi) is a plugin repository
   from VAM plugin manager meant to be used by others as well used by
 
-- [vim2nix](http://github.com/MarcWeber/vim-addon-vim2nix) which generates the
+- [vim2nix](https://github.com/MarcWeber/vim-addon-vim2nix) which generates the
   .nix code