Fix typo

Summary: Fix typo

Reviewed By: yfeldblum

Differential Revision: D31949755

fbshipit-source-id: 31af70aa09a9b15a6bc9ed5567d0ab717956c886

folly/logging/AsyncLogWriter.h

@@ -28,7 +28,7 @@
 namespace folly {
 
 /**
- * An abstract LogWriter implementation that provides functionaility for
+ * An abstract LogWriter implementation that provides functionality for
  * asynchronous IO operations. Users can subclass this class and provide their
  * own IO operation implementation by overriding `performIO` method. This class
  * will automatically manage incoming log messages and call the method in