Fix method theme

[karlaspuldaro]

Fixes #45

This PR fixes the methods level rendering to match functions style.

• CSS selector was not picking up correct element with targeted method class. (this was one problem but it did not fully match functions theme style)
• Adjusts all elements style under method and static method html class to be consistent with functions styling theme
  
  Compared to functions theme rendering:
  

Follow up on separate PR:

• Add a methods.rst example under docs/sphinx-guide/

[CLAassistant]

All committers have signed the CLA.

[karlaspuldaro]

@1ucian0 @javabster This PR is ready for review/comments :)

[HuangJunye]

@karlaspuldaro Thanks for your contribution! This looks great! I will review your PR soon.

[javabster]

This looks great to me, thanks so much @karlaspuldaro!

To answer your questions:

• yes I think it would be great to include the staticmethod html class with these changes too
• a methods.rst example would be helpful in the docs guidelines, but you can add that in a new PR as it is slightly out of scope and not blocking for this work

[karlaspuldaro]

@javabster Thank you for reviewing! I believe all comments have been addressed, and I've created a new issue to track the follow up idea of adding method.rst to docs guide.

[javabster]

LGTM thanks @karlaspuldaro 🚀