Update README.md

Removing reference to extras in readme.

Author: Toni Klopfenstein

README.md

@@ -11,8 +11,7 @@ Repository Contents
 -------------------
 
 * **/examples** - Example sketches for the library (.ino). Run these from the Arduino IDE.
-* **/extras** - Additional documentation for the user. These files are ignored by the IDE.
-* **/src** - Source files for the library (.cpp, .h).
+* * **/src** - Source files for the library (.cpp, .h).
 * **keywords.txt** - Keywords from this library that will be highlighted in the Arduino IDE.
 * **library.properties** - General library properties for the Arduino package manager.