Added XNB Format spec doc (#235)

* Added XNB Format spec doc

* Add missing file

Author: dellis1972

articles/getting_to_know/whatis/content_pipeline/CP_Architecture.md

@@ -40,6 +40,8 @@ The managed code objects created by the Content Processor are serialized into a
 
 The format of data in the .XNB file is tightly coupled to the MonoGame Framework. It is not designed for use by other runtime libraries.
 
+If you are intested in the format of the .XNB files you can view the [XNB specification](XNB Format.docx).
+
 ### Runtime Components
 
 Runtime components of the Content Pipeline support loading and using the transformed game asset by your MonoGame game. These components use the [MonoGame library](../monogame_class_library/index.md), which can be extended to create custom components.

articles/getting_to_know/whatis/content_pipeline/XNB Format.docx

@@ -54,6 +54,7 @@
           "**/videos/**",
           "**/files/**",
           "**/snippets/**",
+          "**/*.docx",
           "CNAME"
         ]
       }

ci.docfx.json

@@ -54,6 +54,7 @@
           "**/videos/**",
           "**/files/**",
           "**/snippets/**",
+          "**/*.docx",
           "CNAME"
         ]
       }