feat: add markdownlint-cli2 (#171)

cli2 is a better cli for markdownlint. It allows to have config files in different directories, and it's also from the same author as the original node.js markdownlint lib.

README.md

@@ -222,6 +222,7 @@ You can view this list in vim with `:help conform-formatters`
 - [latexindent](https://github.com/cmhughes/latexindent.pl) - A perl script for formatting LaTeX files that is generally included in major TeX distributions.
 - [markdown-toc](https://github.com/jonschlinkert/markdown-toc) - API and CLI for generating a markdown TOC (table of contents) for a README or any markdown files.
 - [markdownlint](https://github.com/DavidAnson/markdownlint) - A Node.js style checker and lint tool for Markdown/CommonMark files.
+- [markdownlint-cli2](https://github.com/DavidAnson/markdownlint-cli2) - A fast, flexible, configuration-based command-line interface for linting Markdown/CommonMark files with the markdownlint library.
 - [mdformat](https://github.com/executablebooks/mdformat) - An opinionated Markdown formatter.
 - [mix](https://hexdocs.pm/mix/main/Mix.Tasks.Format.html) - Format Elixir files using the mix format command.
 - [nixfmt](https://github.com/serokell/nixfmt) - nixfmt is a formatter for Nix code, intended to apply a uniform style.
@@ -496,7 +497,6 @@ Retrieve the available formatters for a buffer
 `list_all_formatters(): conform.FormatterInfo[]` \
 List information about all filetype-configured formatters
 
-
 ### get_formatter_info(formatter, bufnr)
 
 `get_formatter_info(formatter, bufnr): conform.FormatterInfo` \

doc/conform.txt

@@ -228,7 +228,9 @@ FORMATTERS                                                    *conform-formatter
 `markdown-toc` - API and CLI for generating a markdown TOC (table of contents)
                for a README or any markdown files.
 `markdownlint` - A Node.js style checker and lint tool for Markdown/CommonMark
-               files.
+`markdownlint-cli2` - A fast, flexible, configuration-based command-line
+                    interface for linting Markdown/CommonMark files with
+                    the markdownlint library
 `mdformat` - An opinionated Markdown formatter.
 `mix` - Format Elixir files using the mix format command.
 `nixfmt` - nixfmt is a formatter for Nix code, intended to apply a uniform

lua/conform/formatters/markdownlint-cli2.lua

@@ -0,0 +1,11 @@
+---@type conform.FileFormatterConfig
+return {
+  meta = {
+    url = "https://github.com/DavidAnson/markdownlint-cli2",
+    description = "A fast, flexible, configuration-based command-line interface for linting Markdown/CommonMark files with the markdownlint library",
+  },
+  command = "markdownlint-cli2",
+  args = { "--fix", "$FILENAME" },
+  exit_codes = { 0, 1 }, -- code 1 is returned when linting/formatter was successful and there were errors
+  stdin = false,
+}