Readme fixes.

Author: dmitry-ivanov

README.md

@@ -102,8 +102,8 @@ class ExampleCommand extends Command
 
 ### Set custom timeout
 
-By default, a mutex is checking for a running command, and if it finds such, it just exits. However, you can manually
-set timeout for a mutex, so it can wait for another command to finish its execution, instead of just quitting immediately.
+By default, the mutex is checking for a running command, and if it finds such, it just exits. However, you can manually
+set the timeout for a mutex, so it can wait for another command to finish its execution, instead of just quitting immediately.
 
 You can change mutex timeout by specifying `$mutexTimeout` field: