[BUGFIX] Use safe preg functions in Rule (#1383)

Part of #1168

Author: oliverklee

CHANGELOG.md

@@ -18,7 +18,7 @@ Please also have a look at our
 
 ### Fixed
 
-- Use typesafe versions of PHP functions (#1379, #1380, #1382)
+- Use typesafe versions of PHP functions (#1379, #1380, #1382, #1383)
 
 ### Documentation
 

src/Rule/Rule.php

@@ -17,6 +17,8 @@
 use Sabberworm\CSS\Value\RuleValueList;
 use Sabberworm\CSS\Value\Value;
 
+use function Safe\preg_match;
+
 /**
  * `Rule`s just have a string key (the rule) and a 'Value'.
  *
@@ -100,7 +102,7 @@ public static function parse(ParserState $parserState, array $commentsBeforeRule
      */
     private static function listDelimiterForRule(string $rule): array
     {
-        if (\preg_match('/^font($|-)/', $rule)) {
+        if (preg_match('/^font($|-)/', $rule) === 1) {
             return [',', '/', ' '];
         }