Update README with documentation link and formatting

Added a line break and a link to the official documentation.

README.md

@@ -2,9 +2,10 @@
 
 [![](https://github.com/yhirose/cpp-httplib/workflows/test/badge.svg)](https://github.com/yhirose/cpp-httplib/actions)
 
-A C++11 single-file header-only cross platform HTTP/HTTPS library.
+A C++11 single-file header-only cross platform HTTP/HTTPS library.<br>
+It's extremely easy to set up. Just include the **[httplib.h](https://raw.githubusercontent.com/yhirose/cpp-httplib/refs/heads/master/httplib.h)** file in your code!
 
-It's extremely easy to set up. Just include the **httplib.h** file in your code!
+**Learn more in the [official documentation](https://yhirose.github.io/cpp-httplib/)**.
 
 > [!IMPORTANT]
 > This library uses 'blocking' socket I/O. If you are looking for a library with 'non-blocking' socket I/O, this is not the one that you want.