fix typo in README

Author: ipanasenko

README.md

@@ -132,7 +132,7 @@ Many of the methods above return change objects. These objects consist of the fo
 
 * `value`: Text content
 * `added`: True if the value was inserted into the new string
-* `removed`: True of the value was removed from the old string
+* `removed`: True if the value was removed from the old string
 
 Note that some cases may omit a particular flag field. Comparison on the flag fields should always be done in a truthy or falsy manner.