Apply suggestions from code review [skip ci]

Author: hjoliver

cylc/flow/job_runner_mgr.py

@@ -373,7 +373,7 @@ def job_kill(self, st_file_path):
 
     @classmethod
     def _create_nn(cls, job_file_path):
-        """Create NN symbolic link, or remove old job logs if they exist.
+        """Create NN symbolic link if necessary, and remove any old job logs.
 
         If NN => 01, remove numbered dirs with submit numbers greater than 01.
 

tests/integration/test_job_runner_mgr.py

@@ -88,10 +88,9 @@ async def test_kill_error(one, start, test_dir, capsys, log_filter):
 async def test_create_nn_new(one, start, test_dir, capsys, log_filter):
     """Test _create_nn. 
 
-    It should the NN symlink.
+    It should create the NN symlink.
     """
     async with start(one):
-        # make it look like the task is running
         itask = one.pool.get_tasks()[0]
 
         workflow_job_log_dir = Path(get_workflow_run_job_dir(one.workflow))