Add pending signals to third tick step

src/Loop/Driver.php

@@ -21,7 +21,7 @@ abstract class Driver
      *
      *  1. Activate watchers created / enabled in the last tick / before `run()`.
      *  2. Execute all enabled defer watchers.
-     *  3. Execute all due timer and actionable stream callbacks, each only once per tick.
+     *  3. Execute all due timer, pending signal and actionable stream callbacks, each only once per tick.
      *
      * The loop MUST continue to run until it is either stopped explicitly, no referenced watchers exist anymore, or an
      * exception is thrown that cannot be handled. Exceptions that cannot be handled are exceptions thrown from an