Add nvim-lazy submodule and add plugin configuration.

pkgsets/nvim/lsp/html.nix

@@ -0,0 +1,16 @@
+{
+  lib,
+  config,
+  pkgs,
+  ...
+}:
+
+lib.optionalString (lib.elem "nvim::lsp::html" config.machine.pkgs) # lua
+  ''
+    local html_capabilities = vim.lsp.protocol.make_client_capabilities()
+    html_capabilities.textDocument.completion.completionItem.snippetSupport = true
+    lspconfig.html.setup({
+      capabilities = html_capabilities,
+      cmd = {"${pkgs.vscode-langservers-extracted}/bin/vscode-html-language-server"}
+    })
+  ''