Update test concatenation of multiple field lines

Author: gapple

tests/ParsingRulesetTrait.php

@@ -31,7 +31,7 @@ public function testParsing(Rule $record): void
         }
 
         try {
-            $raw = implode(',', $record->raw);
+            $raw = implode(', ', $record->raw);
             $parsedValue = Parser::{'parse' . ucfirst($record->header_type)}($raw);
 
             if ($record->must_fail) {

tests/SerializingRulesetTrait.php

@@ -38,7 +38,7 @@ public function testSerializing(Rule $record): void
             }
 
             $this->assertEquals(
-                implode(',', $record->canonical ?? $record->raw),
+                implode(', ', $record->canonical ?? $record->raw),
                 $serializedValue,
                 '"' . $record->name . '" was not serialized to expected value'
             );