Update rn.3-0-12.txt

docs/rn.3-0-12.txt

@@ -3,8 +3,7 @@ Fixed bugs
 * :jirabug:`PT-1611`: ``pt-archiver`` failed to output UTF-8 characters.
 * :jirabug:`PT-1574`: ``pt-online-schema-change`` failed on tables with a nullable unique key and a row with NULL values.
 * :jirabug:`PT-1572`: ENUM fields usage in keys was improved, resulting in higher speed for expressions with sorted ENUM items.
-* :jirabug:`PT-1422`: ``pt-mysql-summary`` could hung up in case of NULL values in a processlist Time column
-
+* :jirabug:`PT-1422`: ``pt-mysql-summary`` could hang when NULL values appear in the processlist Time column.
 Documentation changes
 
 * :jirabug:`PT-1321`: The required MySQL privileges were detailed in `pt-online-schema-change`` documentation