[3.7] bpo-37635: Update arg name for seek() in IO tutorial (GH-16147)

[miss-islington]

Typically, the second positional argument for seek() is whence. That is the POSIX standard name (http://man7.org/linux/man-pages/man3/lseek.3p.html) and the name listed in the documentation for io module (https://docs.python.org/3/library/io.htmlGH-io.IOBase.seek).

The tutorial for IO is the only location where the second positional argument for seek() is referred to as from_what. I suspect this was created at an early point in Python's history, and was never updated (as this section predates the GitHub repository):

$ git grep "from_what"
Doc/tutorial/inputoutput.rst:To change the file object's position, use ``f.seek(offset, from_what)``.  The position is computed
Doc/tutorial/inputoutput.rst:the *from_what* argument.  A *from_what* value of 0 measures from the beginning
Doc/tutorial/inputoutput.rst:the reference point.  *from_what* can be omitted and defaults to 0, using the

For consistency, I am suggesting that the tutorial be updated to use the same argument name as the IO documentation and POSIX standard for seek(), particularly since this is the only location where from_what is being used.

Note: In the POSIX standard, whence is technically the third positional argument, but the first argument fildes (file descriptor) is implicit in Python.

https://bugs.python.org/issue37635
(cherry picked from commit ff603f6)

Co-authored-by: Kyle Stanley aeros167@gmail.com

https://bugs.python.org/issue37635

Automerge-Triggered-By: @pitrou

[pitrou]

+1

[miss-islington]

@aeros167: Status check is done, and it's a success ✅ .