Cover untested code path

Author: fredden

tests/Core/Config/SniffsExcludeArgsTest.php

@@ -136,6 +136,19 @@ public static function dataInvalidSniffs()
                 'suggestion' => 'Standard.Category.Sniff',
             ];
 
+            // Too many dots
+            $data[$argument.'; error-code'] = [
+                'argument'   => $argument,
+                'value'      => 'Standard.Category.Sniff.Code.Extra',
+                'errors'     => [
+                    [
+                        'Standard.Category.Sniff.Code.Extra',
+                        'Too many dots.',
+                    ],
+                ],
+                'suggestion' => 'Standard.Category.Sniff',
+            ];
+
             // All errors are reported in one go.
             $data[$argument.'; two errors'] = [
                 'argument'   => $argument,