fix a few doc typos

found by @juliantaylor

closes gh-917

docs/source/config/plugins.txt

@@ -17,7 +17,8 b' At this point, our plugin system is brand new and the documentation is'
 minimal. If you are interested in creating a new plugin, see the following
 files:
 
-* :file:`IPython/extensions/parallemagic.py`
-* :file:`IPython/extensions/pretty.`
+* :file:`IPython/extensions/parallelmagic.py`
+* :file:`IPython/extensions/autoreload.py`
+* :file:`IPython/extensions/sympyprinting.py`
 
 As well as our documentation on the configuration system and extensions.

docs/source/parallel/parallel_multiengine.txt

@@ -179,7 +179,7 b' dv.block : bool'
     whether to wait for the result, or return an :class:`AsyncResult` object
     immediately
 dv.track : bool
-    whether to instruct pyzmq to track when 
+    whether to instruct pyzmq to track when zeromq is done sending the message.
     This is primarily useful for non-copying sends of numpy arrays that you plan to
     edit in-place.  You need to know when it becomes safe to edit the buffer
     without corrupting the message.