Update README.md

README.md

@@ -17,7 +17,7 @@ Just copy the files to your build tree and use a C++11 compiler
 * Feature rich [call style](#usage-example) using the excellent [cppformat](http://cppformat.github.io/) library.
 * ostream call style is supported too.
 * Extremely fast asynchronous mode (optional) - using lockfree queues and other tricks to reach millions of calls/sec.
-* [Custom](https://github.com/gabime/spdlog/wiki/Custom-formatting) formatting.
+* [Custom](https://github.com/gabime/spdlog/wiki/3.-Custom-formatting) formatting.
 * Multi/Single threaded loggers.
 * Various log targets:
     * Rotating log files.