gh-145642: Match tutorial output to real interpreter output

[SnoopJ]

Closes #145642.

This changeset updates the official tutorial to match real interpreter output for an example that demonstrates escape sequences, namely showing the generated SyntaxWarning.

• Issue: Tutorial does not mention SyntaxWarning for invalid escape sequences #145642

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📚 Documentation preview 📚: https://cpython-previews--145643.org.readthedocs.build/

[SnoopJ]

I should note that this update to the docs contains the text that matches Python 3.14's output, but on Python 3.12 and 3.13 the output is more terse:

>>> print('C:\some\name')
<unknown>:1: SyntaxWarning: invalid escape sequence '\s'
C:\some
ame

So this change should not be backported to the docs for those versions as-is. If the docs for these older versions should also be updated, I can submit a separate PR.

[SnoopJ]

Reworked the example to avoid the invalid escape sequence, per discussion with @nedbat

[picnixz]

I should note that this update to the docs contains the text that matches Python 3.14's output, but on Python 3.12 and 3.13 the output is more terse:

With C:\this\name, is the output for 3.13 the same as the one that you have in this PR? if so, we can backport it to 3.13. 3.12 won't get a backport because it's security-only though

[SnoopJ]

With C:\this\name, is the output for 3.13 the same as the one that you have in this PR? if so, we can backport it to 3.13. 3.12 won't get a backport because it's security-only though

Yep, output is the same on 3.13 and 3.14 so this can be backported.

[miss-islington-app]

Thanks @SnoopJ for the PR, and @nedbat for merging it 🌮🎉.. I'm working now to backport this PR to: 3.13.
🐍🍒⛏🤖

[miss-islington-app]

Thanks @SnoopJ for the PR, and @nedbat for merging it 🌮🎉.. I'm working now to backport this PR to: 3.14.
🐍🍒⛏🤖

[bedevere-app]

GH-145646 is a backport of this pull request to the 3.13 branch.

[bedevere-app]

GH-145647 is a backport of this pull request to the 3.14 branch.