Update README.rst

[LqdBcnAtWork]

• Removed references to Style, Fore, Back, and Cursor.
  • Not part of this projects main goal.
  • The demo's could be considered enough documentation for them. As they're not the primary purpose anyway.
• Removed references to updating Style, Fore, Back, and Cursor.
  • Looks messy,
• Removed mention of autoreset flag in init()
  • This feature seems to be beyond the scope of this project.
  • Perhaps a demo or separate RST/MD file could be created with the purpose of documenting ALL features of this package.
  • This would also be a better spot to discourage the idea of expanding Fore, Back, Style and Cursor.

This is in response to this comment: https://github.com/tartley/colorama/pull/355#issuecomment-1288306104

[tartley]

I don't think removing the documentation of features is a good idea. Just because they are not the package's primary purpose, that isn't a reason to leave them undocumented.