beets: document pluginOverrides

pkgs/tools/audio/beets/default.nix

@@ -2,7 +2,19 @@
 , callPackage
 , fetchFromGitHub
 }:
-
+/*
+** To customize the enabled beets plugins, use the pluginOverrides input to the
+** derivation.
+** Examples:
+**
+** Disabling a builtin plugin:
+** beets.override { pluginOverrides = { beatport.enable = false; }; }
+**
+** Enabling an external plugin:
+** beets.override { pluginOverrides = {
+**   alternatives = { enable = true; propagatedBuildInputs = [ beetsPackages.alternatives ]; };
+** }; }
+*/
 lib.makeExtensible (self: {
   beets = self.beets-stable;