Sand Castle Help file builder and System.valuetuple.xml

I tried building a Sand castle help file for a .net solution file that included 5-6 projects.

The solution built fine in visual studio.

I took care that in the Properties->Build-> xml documentation file option is checked for every individual project.

However, when i tried building help file with the solution as source in Sandcastle I got errors.

Looks like its a known issue came across by few already.Please see the links below:-

https://github.com/EWSoftware/SHFB/issues/595 

https://stackoverflow.com/questions/47262746/how-to-ignore-the-xml-documentation-files-for-reference-dll-in-sandcastle

It was quite cumbersome to get this file built as there were issues with xml tags in System.ValueTuple.Xml which was being referenced. I had to manually correct a bunch of the broken tags in the file.

I just created the help file, fixing all help file build errors in Sandcastle.