Doc: Add docstrings for drawing, text, and font functions in TFT_eSPI…

[YonLiud]

This pull request adds detailed docstrings to the methods and functions of the TFT_eSPI class. The updates include:

• Drawing Functions: Added docstrings for functions like drawCircle, fillCircle, drawEllipse, fillEllipse, and pushImage, providing clear descriptions of their purpose and parameters.
• Text Functions: Documented text-related methods such as setTextFont, setFreeFont, and setTextColor, including details on how they manage text rendering.
• Miscellaneous Functions: Updated docstrings for various utility functions, including setAddrWindow, setPivot, and readcommand8.

The goal is to enhance code readability and maintainability by providing consistent and comprehensive documentation for each function. This will help developers understand the purpose and usage of each method more effectively.

Please note that while docstrings have been added to most functions, not all functions are documented in this pull request. If additional documentation for any remaining functions is desired, please let me know, and I will be happy to add it.

[YonLiud]

Note: English is not my first language, and I apologize for any spelling or grammatical mistakes that may be present in the documentation. Thank you for your understanding.