Fix dotnet/docs#8427 remove misleading remarks (dotnet#645)

## Summary

Removes duplicate and out of place information about URL Encoding from the `JavaScriptStringEncode` methods, where it may be misleading. The documentation for `UrlEncode` is already more complete, and this isn't relevant to JavaScript specific string encoding.

Fixes dotnet/docs#8427

xml/System.Web/HttpUtility.xml

@@ -516,8 +516,6 @@
 ## Remarks  
  This method encodes strings. For instance, single quotation marks and double quotation marks are included as `\'` and `\"` in the encoded string.  
   
- URL encoding makes sure that all browsers correctly transmit text in URL strings. Characters such as a question mark (?), ampersand (&), slash (/), and spaces might be truncated or corrupted by some browsers. Therefore, these characters must be encoded in `a` elements or in query strings where the strings can be re-sent by a browser in a request string.  
-  
  ]]></format>
         </remarks>
       </Docs>
@@ -1832,4 +1830,4 @@
       </Docs>
     </Member>
   </Members>
-</Type>
+</Type>