feat: add linter plugin (#699)

Author: fredrikaverpil

init.lua

@@ -831,6 +831,7 @@ require('lazy').setup({
   --
   -- require 'kickstart.plugins.debug',
   -- require 'kickstart.plugins.indent_line',
+  -- require 'kickstart.plugins.lint',
 
   -- NOTE: The import below can automatically add your own plugins, configuration, etc from `lua/custom/plugins/*.lua`
   --    This is the easiest way to modularize your config.

lua/kickstart/plugins/lint.lua

@@ -0,0 +1,55 @@
+return {
+
+  { -- Linting
+    'mfussenegger/nvim-lint',
+    event = { 'BufReadPre', 'BufNewFile' },
+    config = function()
+      local lint = require 'lint'
+      lint.linters_by_ft = {
+        markdown = { 'markdownlint' },
+      }
+
+      -- To allow other plugins to add linters to require('lint').linters_by_ft,
+      -- instead set linters_by_ft like this:
+      -- lint.linters_by_ft = lint.linters_by_ft or {}
+      -- lint.linters_by_ft['markdown'] = { 'markdownlint' }
+      --
+      -- However, note that this will enable a set of default linters,
+      -- which will cause errors unless these tools are available:
+      -- {
+      --   clojure = { "clj-kondo" },
+      --   dockerfile = { "hadolint" },
+      --   inko = { "inko" },
+      --   janet = { "janet" },
+      --   json = { "jsonlint" },
+      --   markdown = { "vale" },
+      --   rst = { "vale" },
+      --   ruby = { "ruby" },
+      --   terraform = { "tflint" },
+      --   text = { "vale" }
+      -- }
+      --
+      -- You can disable the default linters by setting their filetypes to nil:
+      -- lint.linters_by_ft['clojure'] = nil
+      -- lint.linters_by_ft['dockerfile'] = nil
+      -- lint.linters_by_ft['inko'] = nil
+      -- lint.linters_by_ft['janet'] = nil
+      -- lint.linters_by_ft['json'] = nil
+      -- lint.linters_by_ft['markdown'] = nil
+      -- lint.linters_by_ft['rst'] = nil
+      -- lint.linters_by_ft['ruby'] = nil
+      -- lint.linters_by_ft['terraform'] = nil
+      -- lint.linters_by_ft['text'] = nil
+
+      -- Create autocommand which carries out the actual linting
+      -- on the specified events.
+      local lint_augroup = vim.api.nvim_create_augroup('lint', { clear = true })
+      vim.api.nvim_create_autocmd({ 'BufEnter', 'BufWritePost', 'InsertLeave' }, {
+        group = lint_augroup,
+        callback = function()
+          require('lint').try_lint()
+        end,
+      })
+    end,
+  },
+}