feat: add support for kdlfmt

Closes #509

README.md

@@ -267,6 +267,7 @@ You can view this list in vim with `:help conform-formatters`
 - [jsonnetfmt](https://github.com/google/go-jsonnet/tree/master/cmd/jsonnetfmt) - jsonnetfmt is a command line tool to format jsonnet files.
 - [just](https://github.com/casey/just) - Format Justfile.
 - [kcl](https://www.kcl-lang.io/docs/tools/cli/kcl/fmt) - The KCL Format tool modifies the files according to the KCL code style.
+- [kdlfmt](https://github.com/hougesen/kdlfmt) - A formatter for kdl documents.
 - [ktfmt](https://github.com/facebook/ktfmt) - Reformats Kotlin source code to comply with the common community standard conventions.
 - [ktlint](https://ktlint.github.io/) - An anti-bikeshedding Kotlin linter with built-in formatter.
 - [kulala-fmt](https://github.com/mistweaverco/kulala-fmt) - An opinionated .http and .rest files linter and formatter.

doc/conform.txt

@@ -369,6 +369,7 @@ FORMATTERS                                                    *conform-formatter
 `jsonnetfmt` - jsonnetfmt is a command line tool to format jsonnet files.
 `just` - Format Justfile.
 `kcl` - The KCL Format tool modifies the files according to the KCL code style.
+`kdlfmt` - A formatter for kdl documents.
 `ktfmt` - Reformats Kotlin source code to comply with the common community
         standard conventions.
 `ktlint` - An anti-bikeshedding Kotlin linter with built-in formatter.

lua/conform/formatters/kdlfmt.lua

@@ -0,0 +1,10 @@
+---@type conform.FileFormatterConfig
+return {
+  meta = {
+    url = "https://github.com/hougesen/kdlfmt",
+    description = "A formatter for kdl documents.",
+  },
+  command = "kdlfmt",
+  args = { "format", "-" },
+  stdin = true,
+}