The changes made to src/lib.rs on July 5, 2025, caused the interface definitions in winpty.pyi to significantly diverge from the actual implementation.

This PR addresses the mismatch between winpty.pyi and the real interface by:

1. Adding the missing self parameter to cancel_io().
2. Removing the non-existent method read_stderr.
3. Removing the unused length parameter from the read() method.
4. Removing the non-existent encoding parameter from __init__().
5. General code cleanup and formatting improvements.

Additionally, this PR fixes minor type-related issues in ptyprocess.py:

1. Removing the unused import import codecs.
2. Changing the byte literal b'0011Ignore' to the string '0011Ignore' to prevent a potential TypeError: encoding without a string argument.