Fix typo in "Unexpected token" error

Author: vojtech-dobes

src/GrammarProcessing/LexicalGrammar.php

@@ -154,7 +154,7 @@ private function throwUnexpectedTokenException(
 	{
 		throw new UnexpectedTokenException(
 			sprintf(
-				"Unxpected token '%s'",
+				"Unexpected token '%s'",
 				strlen($value) > 12
 					? substr($value, 0, 10) . '... (truncated)'
 					: $value,

tests/cases/LexicalGrammar.cases.php

@@ -90,6 +90,6 @@
 			'Base' => new Vojtechdobes\GrammarProcessing\Vocabulary\Regexp('a'),
 		],
 		'ab',
-		"Unxpected token 'b' (line 1, col 2)",
+		"Unexpected token 'b' (line 1, col 2)",
 	],
 ];