nvim: move to services we do not specify a pkgset

pkgsets/nvim/lsp/yaml.nix

@@ -1,26 +0,0 @@
-{
-  lib,
-  config,
-  pkgs,
-  ...
-}:
-
-lib.optionalAttrs (lib.elem "nvim::lsp::yaml" config.machine.pkgs) {
-  yamlls = {
-    cmd = [
-      "${pkgs.yaml-language-server}/bin/yaml-language-server"
-      "--stdio"
-    ];
-    settings = {
-      yaml = {
-        schemaStore = {
-          # Disable to use Store from SchemaStore-nvim plugin
-          enable = false;
-          # Avoid TypeError: Cannot read properties of undefined (reading 'length')
-          url = "";
-        };
-        schemas = _: "require('schemastore').yaml.schemas()";
-      };
-    };
-  };
-}