treewide: automatically md-convert option descriptions

the conversion procedure is simple:

 - find all things that look like options, ie calls to either `mkOption`
   or `lib.mkOption` that take an attrset. remember the attrset as the
   option
 - for all options, find a `description` attribute who's value is not a
   call to `mdDoc` or `lib.mdDoc`
 - textually convert the entire value of the attribute to MD with a few
   simple regexes (the set from mdize-module.sh)
 - if the change produced a change in the manual output, discard
 - if the change kept the manual unchanged, add some text to the
   description to make sure we've actually found an option. if the
   manual changes this time, keep the converted description

this procedure converts 80% of nixos options to markdown. around 2000
options remain to be inspected, but most of those fail the "does not
change the manual output check": currently the MD conversion process
does not faithfully convert docbook tags like <code> and <package>, so
any option using such tags will not be converted at all.

1 files changed, 5 insertions, 5 deletions

diff --git a/nixos/modules/config/system-path.nix b/nixos/modules/config/system-path.nix
index 875c4c9c441..de980e7383b 100644
--- a/nixos/modules/config/system-path.nix
+++ b/nixos/modules/config/system-path.nix
@@ -64,14 +64,14 @@ in
         type = types.listOf types.package;
         default = [];
         example = literalExpression "[ pkgs.firefox pkgs.thunderbird ]";
-        description = ''
+        description = lib.mdDoc ''
           The set of packages that appear in
           /run/current-system/sw.  These packages are
           automatically available to all users, and are
           automatically updated every time you rebuild the system
           configuration.  (The latter is the main difference with
           installing them in the default profile,
-          <filename>/nix/var/nix/profiles/default</filename>.
+          {file}`/nix/var/nix/profiles/default`.
         '';
       };
 
@@ -109,20 +109,20 @@ in
         # to work.
         default = [];
         example = ["/"];
-        description = "List of directories to be symlinked in <filename>/run/current-system/sw</filename>.";
+        description = lib.mdDoc "List of directories to be symlinked in {file}`/run/current-system/sw`.";
       };
 
       extraOutputsToInstall = mkOption {
         type = types.listOf types.str;
         default = [ ];
         example = [ "doc" "info" "devdoc" ];
-        description = "List of additional package outputs to be symlinked into <filename>/run/current-system/sw</filename>.";
+        description = lib.mdDoc "List of additional package outputs to be symlinked into {file}`/run/current-system/sw`.";
       };
 
       extraSetup = mkOption {
         type = types.lines;
         default = "";
-        description = "Shell fragments to be run after the system environment has been created. This should only be used for things that need to modify the internals of the environment, e.g. generating MIME caches. The environment being built can be accessed at $out.";
+        description = lib.mdDoc "Shell fragments to be run after the system environment has been created. This should only be used for things that need to modify the internals of the environment, e.g. generating MIME caches. The environment being built can be accessed at $out.";
       };
 
     };