docs: move "What is Content Negotiation?" to content_negotiation.rst

Author: kenjis

user_guide_src/source/incoming/content_negotiation.rst

@@ -13,6 +13,26 @@ can handle this for you.
     :local:
     :depth: 2
 
+****************************
+What is Content Negotiation?
+****************************
+
+At it's heart Content Negotiation is simply a part of the HTTP specification that allows a single
+resource to serve more than one type of content, allowing the clients to request the type of
+data that works best for them.
+
+A classic example of this is a browser that cannot display PNG files can request only GIF or
+JPEG images. When the server receives the request, it looks at the available file types the client
+is requesting and selects the best match from the image formats that it supports, in this case
+likely choosing a JPEG image to return.
+
+This same negotiation can happen with four types of data:
+
+* **Media/Document Type** - this could be image format, or HTML vs. XML or JSON.
+* **Character Set** - The character set the returned document should be set in. Typically is UTF-8.
+* **Document Encoding** - Typically the type of compression used on the results.
+* **Document Language** - For sites that support multiple languages, this helps determine which to return.
+
 *****************
 Loading the Class
 *****************

user_guide_src/source/incoming/message.rst

@@ -11,25 +11,6 @@ This class is the parent class that both the :doc:`Request Class </incoming/requ
 negotiation methods, may apply only to a request or response, and not the other one, but they have
 been included here to keep the header methods together.
 
-What is Content Negotiation?
-============================
-
-At it's heart Content Negotiation is simply a part of the HTTP specification that allows a single
-resource to serve more than one type of content, allowing the clients to request the type of
-data that works best for them.
-
-A classic example of this is a browser that cannot display PNG files can request only GIF or
-JPEG images. When the server receives the request, it looks at the available file types the client
-is requesting and selects the best match from the image formats that it supports, in this case
-likely choosing a JPEG image to return.
-
-This same negotiation can happen with four types of data:
-
-* **Media/Document Type** - this could be image format, or HTML vs. XML or JSON.
-* **Character Set** - The character set the returned document should be set in. Typically is UTF-8.
-* **Document Encoding** - Typically the type of compression used on the results.
-* **Document Language** - For sites that support multiple languages, this helps determine which to return.
-
 ***************
 Class Reference
 ***************