Fix sonar recommendations

Closes #383

src/Html2Markdown/Replacement/HtmlParser.cs

@@ -221,9 +221,11 @@ private static string GetSyntaxHighlightLanguage(HtmlNode node)
 			return string.Empty;
 		}
 
-		return classAttributeValue.StartsWith("lang") 
-			? classAttributeValue.Split('-').Last() 
-			: classAttributeValue;
+		if (!classAttributeValue.StartsWith("lang")) return classAttributeValue;
+		var split =  classAttributeValue.Split('-');
+
+		return split[^1]; // PERFORMANCE: https://sonarcloud.io/organizations/baynezy/rules?open=csharpsquid%3AS6608&rule_key=csharpsquid%3AS6608
+
 	}
 
 	internal static string ReplaceBlockquote(string html)

src/Html2Markdown/Replacement/PatternReplacer.cs

@@ -11,7 +11,8 @@ public class PatternReplacer : IReplacer
 	public string Replacement { get; init; }
 	public string Replace(string html)
 	{
-		var regex = new Regex(Pattern);
+		// SECURITY: https://sonarcloud.io/organizations/baynezy/rules?open=csharpsquid%3AS6444&rule_key=csharpsquid%3AS6444
+		var regex = new Regex(Pattern, RegexOptions.None, TimeSpan.FromSeconds(1));
 
 		return regex.Replace(html, Replacement);
 	}