[skip ci] clarify new plugin_arg description

Author: oesteban

doc/users/plugins.rst

@@ -82,8 +82,8 @@ Optional arguments::
   exceed the total amount of resources available (memory and threads), when
   ``False`` (default), only a warning will be issued.
 
-  maxtasksperchild : refresh the workers after this specific number of nodes
-  run (default: 10).
+  maxtasksperchild : number of nodes to run on each process before refreshing 
+  the worker (default: 10).
   
 
 To distribute processing on a multicore machine, simply call::

nipype/pipeline/plugins/multiproc.py

@@ -105,8 +105,8 @@ class MultiProcPlugin(DistributedPluginBase):
     - scheduler: sort jobs topologically (``'tsort'``, default value)
         or prioritize jobs by, first, memory consumption and, second,
         number of threads (``'mem_thread'`` option).
-    - maxtasksperchild: refresh workers after a certain amount of tasks
-        run (and release resources).
+    - maxtasksperchild: number of nodes to run on each process before
+        refreshing the worker (default: 10).
 
     """