nvim: lsp: Enable shellcheck as diagnostics source for null-ls

nvim/.config/nvim/lua/lsp.lua

@@ -36,7 +36,10 @@ end
 -- See https://github.com/jose-elias-alvarez/null-ls.nvim/issues/38
 -- Required by nvim-lsp-ts-utils to provide ESLint code actions, diagnostics
 -- and formatting.
-null_ls.config {}
+local null_ls_sources = {
+    null_ls.builtins.diagnostics.shellcheck,
+}
+null_ls.config({ sources = null_ls_sources })
 nvim_lsp["null-ls"].setup {}
 
 local ts_utils_setup = function(client, bufnr, opts)