feat: use .ls-lint.yaml file as default configuration file

The .ls-lint.yaml file is now used as the default configuration file
The .ls-lint.yml file is still supported for backward compatibility.

The choice was made to prioritize the .ls-lint.yaml file for its clarity
and alignment with YAML file naming conventions.

Author: ccoVeille

README.md

@@ -11,8 +11,8 @@ An extremely fast directory and filename linter - Bring some structure to your p
 ![npm](https://badgen.net/static/npm%20downloads%20total/9M+/green)
 <a href="https://www.npmjs.com/package/@ls-lint/ls-lint"><img src="https://img.shields.io/npm/l/@ls-lint/ls-lint.svg?sanitize=true" alt="License"></a>
 
-- Minimal setup with simple rules managed in one single or multiple `.ls-lint.yml` files
-- Works for directory and file names - all extensions supported - full unicode support
+- Minimal setup with simple rules managed in one single or multiple `.ls-lint.yaml` (or `.ls-lint.yml`) files
+- Works for directory and file names - all extensions supported - full Unicode support
 - Incredibly fast - lints thousands of files and directories in milliseconds
 - Support for Windows, MacOS and Linux + [NPM Package](https://www.npmjs.com/package/@ls-lint/ls-lint) + [GitHub Action](https://github.com/ls-lint/action) + [Homebrew](https://formulae.brew.sh/formula/ls-lint) + Docker
 - Trusted by [Renovate](https://github.com/renovatebot/renovate/blob/main/.ls-lint.yml), [Terser](https://github.com/terser/terser/blob/master/.ls-lint.yml) and many more
@@ -34,7 +34,7 @@ The full documentation can be found at [ls-lint.org](https://ls-lint.org)
 
 ## Demo
 
-### Configuration `.ls-lint.yml`
+### Configuration `.ls-lint.yaml`
 
 ```yaml
 ls:

cmd/ls_lint/main.go

@@ -11,16 +11,24 @@ import (
 	"slices"
 	"strings"
 
+	"gopkg.in/yaml.v3"
+
 	"github.com/loeffel-io/ls-lint/v2/internal/config"
 	"github.com/loeffel-io/ls-lint/v2/internal/debug"
 	_flag "github.com/loeffel-io/ls-lint/v2/internal/flag"
 	"github.com/loeffel-io/ls-lint/v2/internal/linter"
 	"github.com/loeffel-io/ls-lint/v2/internal/rule"
-	"gopkg.in/yaml.v3"
 )
 
 var Version = "dev"
 
+const (
+	// expected ls-lint config file
+	lsLintConfigFile = ".ls-lint.yaml"
+	// former ls-lint config file, supported for backward compatibility
+	lsLintConfigFileLegacy = ".ls-lint.yml"
+)
+
 func main() {
 	var err error
 	exitCode := 0
@@ -57,7 +65,15 @@ func main() {
 	}
 
 	if len(flagConfig) == 0 {
-		flagConfig = _flag.Config{".ls-lint.yml"}
+		// no config files was provided by the --config flag
+
+		// We try the .yaml file first
+		configFile := lsLintConfigFile
+		if _, err := os.Stat(lsLintConfigFileLegacy); err == nil {
+			// but we use the .yml one if it exists
+			configFile = lsLintConfigFileLegacy
+		}
+		flagConfig = _flag.Config{configFile}
 	}
 
 	filesystem := os.DirFS(*flagWorkdir)