Replace redundant StringBuilder append String.subString with append CharSequence

http-service/src/main/java/net/runelite/http/service/cache/CacheService.java

@@ -104,7 +104,7 @@ public class CacheService
 	{
 		String hashStr = BaseEncoding.base16().encode(archiveEntry.getHash());
 		String path = new StringBuilder()
-			.append(hashStr.substring(0, 2))
+			.append(hashStr, 0, 2)
 			.append('/')
 			.append(hashStr.substring(2))
 			.toString();