Fix test to obey added documentation

Author: koppor

src/test/java/org/jabref/model/strings/StringUtilTest.java

@@ -21,7 +21,7 @@ void StringUtilClassIsSmall() throws Exception {
         Path path = Paths.get("src", "main", "java", StringUtil.class.getName().replace('.', '/') + ".java");
         int lineCount = Files.readAllLines(path, StandardCharsets.UTF_8).size();
 
-        assertTrue(lineCount <= 749, "StringUtil increased in size to " + lineCount + ". "
+        assertTrue(lineCount <= 756, "StringUtil increased in size to " + lineCount + ". "
                 + "We try to keep this class as small as possible. "
                 + "Thus think twice if you add something to StringUtil.");
     }