testers.lycheeLinkCheck: Edit documentation and messages

Check a packaged static site's links with the [`lychee` package](https://search.nixos.org/packages?show=lychee&type=packages&query=lychee).

You may use Nix to reproducibly build documentation sites and other static sites.

You may use Nix to reproducibly build static websites, such as for software documentation.

Some packages will install documentation in their `out` or `doc` outputs, or maybe you have dedicated package where you've made your static site reproducible by running a generator, such as [Hugo](https://gohugo.io/) or [mdBook](https://rust-lang.github.io/mdBook/), in a derivation.

If you have a static site that can be built with Nix, you can use `lycheeLinkCheck` to check that the hyperlinks in your site are correct, and do so as part of your Nix workflow and CI.

`remap` (attribe set, optional) {#tester-lycheeLinkCheck-param-remap}

: An attribute set where the attribute names are regular expressions.

  The values should be strings, derivations or path values.

  The values should be strings, derivations, or path values.

  In the returned check's default configuration, external URLs are only checked when you run the `.online` attribute.

  By adding remappings, you can check offline that URLs to external resources are correct, by providing a file system based stand-in.

  By adding remappings, you can check offline that URLs to external resources are correct, by providing a stand-in from the file system.

  Before checking the existence of a URL, the regular expressions are matched and replaced by their corresponding values.

  }

  ```

  Store path in the attribute values are automatically prefixed with `file://`, because lychee requires this for paths in the file system.

  Store paths in the attribute values are automatically prefixed with `file://`, because lychee requires this for paths in the file system.

  If this is a problem, or if you need to control the order in which replacements are performed, use `extraConfig.remap` instead.

`extraConfig` (attribute set) {#tester-lycheeLinkCheck-param-extraConfig}

    else s;

  withCheckedName = name:

    throwIf

      (hasInfix " " name)

      "lycheeLinkCheck: remap patterns must not contain spaces. A space marks the end of the regex in lychee.toml. Please change attribute name remap.${escapeNixString name}";

    throwIf (hasInfix " " name) ''

      lycheeLinkCheck: remap patterns must not contain spaces.

      A space marks the end of the regex in lychee.toml.

      Please change attribute name 'remap.${escapeNixString name}'

    '';

  # See https://nixos.org/manual/nixpkgs/unstable/#tester-lycheeLinkCheck

  # or doc/builders/testers.chapter.md