Adding list and block functionality for Contains function

[pratikmota]

Changes:

1. Contains working with Block
2. Contains working with List
   
3. Added test cases
4. Doubts:

• After adding test cases for contain if i run ../rye main.rye test , it is not displaying my test case result. (group "contains")
• Also if we run ../rye main.rye doc > builtins.html , then there are different files are generated also builtins.html is coming blank.
• Is there any recent changes for test / test case/ document related?

[InvoiceFox]

Hi Pratik! Thank you for your improvements! I redid the tests and documentation because it's separated to multiple files now. The one file of docs was getting too large so it was confusing. I will add your tests to appropriate file. Docs now generate multiple html files, that aren't added to github, but generated on the fly and uploaded.
I also changed so that contrib is now a normal folder, not a submodule any more and there were some other cleaning ups.
Thanks again for you PR!