Update broken link found by linkchecker and edit a few small things on ONNX integ

doc/sphinx/source/frameworks/onnx_integ.rst

 .. frameworks/onnx_integ.rst:
 
-
 ONNX Support
 ============
 
-
 nGraph is able to import and execute ONNX models. Models are converted to 
-nGraph's internal representation and converted to ``Function`` objects, which 
-can be compiled and executed on one of nGraph's backends.
+nGraph's :abbr:`Intermediate Representation (IR)` and converted to ``Function`` 
+objects, which can be compiled and executed with nGraph backends.
 
 You can use nGraph's Python API to run an ONNX model and nGraph can be used 
-as an ONNX backend using the add-on package `nGraph ONNX`_.
+as a backend to ONNX with the add-on package `nGraph ONNX`_.
 
 
 .. note:: In order to support ONNX, nGraph must be built with the 
-   ``NGRAPH_ONNX_IMPORT_ENABLE`` flag. See `Building nGraph-ONNX 
-   <ngraph_onnx_building>`_ for more information. All nGraph packages 
-   published on PyPI are built with ONNX support.
+   ``NGRAPH_ONNX_IMPORT_ENABLE`` flag. See `Building nGraph-ONNX`_ for more 
+   information. All nGraph packages published on PyPI are built with ONNX 
+   support.
 
 
 Installation
@@ -91,9 +89,9 @@ data:
 
 
 Find more information about nGraph and ONNX in the 
-`nGraph ONNX`_ GitHub repository.
+`nGraph ONNX`_ GitHub\* repository.
 
 
 .. _ngraph ONNX: https://github.com/NervanaSystems/ngraph-onnx
-.. _ngraph ONNX building: https://github.com/NervanaSystems/ngraph-onnx/blob/master/BUILDING.md
+.. _Building nGraph-ONNX: https://github.com/NervanaSystems/ngraph-onnx/blob/master/BUILDING.md
 .. _ONNX model zoo: https://github.com/onnx/models