Summary

Update documentation to clearly state that thefile argument passed toopen() is stored as thename attribute of the returned file object.

Changes Made

1. Doc/library/functions.rst: Added explicit documentation for theopen() function
2. Doc/library/io.rst: Updated documentation forFileIO.name and added missingIOBase.name attribute

Key Clarifications

• Thename attribute stores exactly what was passed as thefile argument
• It can be string, bytes, integer file descriptor, or other representation
• This behavior is preserved for backward compatibility
• Added.. versionchanged:: 3.13 directive to document the clarification

Testing

• Verified documentation builds correctly
• Behavior matches existing Python implementation
• Cross-references between functions.rst and io.rst are consistent

Closesgh-62734

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