Suggest appending (?) to excludePaths entry

Author: ondrejmirtes

src/Command/CommandHelper.php

@@ -362,6 +362,11 @@ public static function begin(
 				$errorOutput->writeLineFormatted($error);
 				$errorOutput->writeLineFormatted('');
 			}
+
+			$errorOutput->writeLineFormatted('If the excluded path can sometimes exist, append <fg=cyan>(?)</>');
+			$errorOutput->writeLineFormatted('to its config entry to mark it as optional.');
+			$errorOutput->writeLineFormatted('');
+
 			throw new InceptionNotSuccessfulException();
 		} catch (ValidationException $e) {
 			foreach ($e->getMessages() as $message) {