ftplugin: add dart lsp

nvim/ftplugin/dart.lua

@@ -0,0 +1,18 @@
+-- Exit if the language server isn't available
+if vim.fn.executable('dart') ~= 1 then
+  return
+end
+
+local root_files = {
+  '.git',
+}
+
+local lsp = require('user.lsp')
+
+vim.lsp.start {
+  name = 'dartls',
+  cmd = { 'dart', 'language-server', '--protocol=lsp' },
+  root_dir = vim.fs.dirname(vim.fs.find(root_files, { upward = true })[1]),
+  capabilities = lsp.make_client_capabilities(),
+  on_attach = lsp.on_attach,
+}