Update MIME docstring (#56942)

Closes #56768

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Co-authored-by: Steven G. Johnson <stevenj@mit.edu>
Co-authored-by: Max Horn <max@quendi.de>
Co-authored-by: Dilum Aluthge <dilum@aluthge.com>
Co-authored-by: Andy Dienes <51664769+adienes@users.noreply.github.com>

Nathan Boyer committed 1d ago

64dc8d4d48d18fd7f68c2207d1bc6160a609407f

Parent: c3b914f

Committed by GitHub <noreply@github.com> on 3/25/2026, 12:52:24 PM