ESLint: Improve regex for valid-sprintf rule to handle '%%'

[im3dabasia]

Fixes: #52787

What?

Updated the regex in the valid-sprintf ESLint rule to correctly handle escaped percent signs (%%). Added 4 new test cases that cover various scenarios involving %%.

Why?

The current regex fails to handle cases like sprintf('Rotated at %d %% degrees', 90) by mistakenly flagging valid format strings with escaped percent signs as incorrect. This update ensures proper handling of %d %% and similar cases.

Screenshots or screencast

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Co-authored-by: im3dabasia <[email protected]>
Co-authored-by: swissspidy <[email protected]>
Co-authored-by: colorful-tones <[email protected]>

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[swissspidy]

Nice, thank you!

[im3dabasia]

Hi @swissspidy ,

I wanted to check if this change is likely to be merged in the upcoming release or if it might take a bit longer.

[t-hamano]

Thanks for solving this issue! With the improved ESLint rules, the issues mentioned here may also be addressed:

Ideally, the string could be simplified to %d%%. Unfortunately, ESLint currently considers this an error.