Excluded path: include example for optional path

Make more clear how to mark an excluded path optional, with the use of `(?)` suffix

Author: thePanz

src/Command/CommandHelper.php

@@ -380,7 +380,8 @@ public static function begin(
 			}
 
 			$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('to its config entry to mark it as optional. Example:');
+			$errorOutput->writeLineFormatted(' <fg=cyan>- path/something (?)</>');
 			$errorOutput->writeLineFormatted('');
 
 			throw new InceptionNotSuccessfulException();