ref(bootstrap.py): add eprint function

[pouriya]

Implemented a 3-line function called eprint which is just like print but for stderr. So each print(..., file=sys.stderr) becomes eprint(...).

Testing eprint function:

$ cat eprint.py

import sys

def eprint(*args, **kwargs):
	kwargs['file'] = sys.stderr
	print(*args, **kwargs)

eval('eprint({})'.format(sys.argv[1]))

$ python3 eprint.py '"hello"'
hello
$

$ python3 eprint.py '"hello"' 2>/dev/null
$

$ python3 eprint.py '"hello", "world", flush=True, file=sys.stdout'                                             
hello world
$

$ python3 eprint.py '"hello", "world", flush=True, file=sys.stdout' 2>/dev/null
$

[rustbot]

Thanks for the pull request, and welcome! The Rust team is excited to review your changes, and you should hear from @albertlarsan68 (or someone else) soon.

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[albertlarsan68]

Thanks for the PR, and welcome!
@bors r+ rollup

[bors]

📌 Commit 598f11a has been approved by albertlarsan68

It is now in the queue for this repository.