Add language support, fix exception typo

Author: MGatner

src/Assets.php

@@ -112,7 +112,7 @@ protected function tag(string $file)
 			break;
 
 			default:
-				throw AssetsException::forUnsupportExtension($extension);
+				throw AssetsException::forUnsupportedExtension($extension);
 
 		endswitch;
 	}

src/Exceptions/AssetsException.php

@@ -5,8 +5,8 @@
 
 class AssetsException extends FrameworkException implements ExceptionInterface
 {
-	public static function forUnsupportExtension(string $extension = null)
+	public static function forUnsupportedExtension(string $extension = null)
 	{
-		return new static("Unsupported file extension: '{$extension}'");
+		return new static(lang('Assets.unsupportedExtension', [$extension]));
 	}
 }

src/Language/en/Assets.php

@@ -0,0 +1,5 @@
+<?php
+
+return [
+	'unsupportedExtension'  => 'Unsupported file extension: "{0}"',
+];