fix formatting and links

source/tutorials/module-system/module-system.md

@@ -67,11 +67,11 @@ Start by changing the first line in `default.nix`:
 
 ```{code-block} diff
 :caption: default.nix
-- { ... }:
-+ { lib, ... }:
-{
+-{ ... }:
++{ lib, ... }:
+ {
 
-}
+ }
 ```
 
 Now the module is a function which takes *at least* one argument, called `lib`, and may accept other arguments (expressed by the ellipsis `...`).
@@ -97,7 +97,7 @@ Change `default.nix` to include the following declaration:
 ```{code-block} diff
 :caption: default.nix
  { lib, ... }: {
-
++
 + options = {
 +   scripts.output = lib.mkOption {
 +     type = lib.types.lines;
@@ -204,12 +204,12 @@ Update `default.nix` by changing the value of `scripts.output` to the following
 
 ```{code-block} diff
 :caption: default.nix
-   config = {
--    scripts.output = 42;
-+    scripts.output = ''
-+      ./map size=640x640 scale=2 | feh -
-+    '';
-   };
+  config = {
+-   scripts.output = 42;
++   scripts.output = ''
++     ./map size=640x640 scale=2 | feh -
++   '';
+  };
 ```
 
 ## Interlude: reproducible scripts

source/tutorials/packaging-existing-software.md

@@ -141,7 +141,7 @@ in
 This allows you to run `nix-build -A hello` to realize the derivation in `hello.nix`, similar to the current convention used in Nixpkgs.
 
 :::{note}
-[`callPackage`] automatically passes attributes from `pkgs` to the given function, if they match attributes required by that function's argument attrset.
+`callPackage` automatically passes attributes from `pkgs` to the given function, if they match attributes required by that function's argument attribute set.
 
 In this case, `callPackage` will supply `lib`, `stdenv`, and `fetchzip` to the function defined in `hello.nix`.
 :::
@@ -643,6 +643,7 @@ Adjust your `installPhase` to call the appropriate hooks:
 # ...
 
 ```
+
 ## A successful build
 
 Running the `nix-build` command once more will finally do what you want, repeatably.
@@ -658,15 +659,13 @@ default.nix hello.nix icat.nix result
 ## References
 
 - [Nixpkgs Manual - Standard Environment](https://nixos.org/manual/nixpkgs/unstable/#part-stdenv)
-- [Nix Pills - `callPackage` Design Pattern][`callPackage`]
-
-[`callPackage`]: https://nixos.org/guides/nix-pills/callpackage-design-pattern.html
 
 ## Next steps
 
 - [Add your own new packages to Nixpkgs](https://github.com/NixOS/nixpkgs/blob/master/CONTRIBUTING.md)
   - [](../contributing/how-to-contribute.md)
   - [](../contributing/how-to-get-help.md)
+- [](callpackage-tutorial)
 - [](sharing-dependencies)
 - [](automatic-direnv)
 - [](python-dev-environment)