PEP 747: Clarify that TypeForm(T) is always a TypeForm[T]

[davidfstr]

• Change is either:
  • To a Draft PEP
  • To an Accepted or Final PEP, with Steering Council approval
  • To fix an editorial issue (markup, typo, link, header, etc)
• PR title prefixed with PEP number (e.g. PEP 123: Summary of changes)

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Integrates feedback from Jukka (a Typing Council member) received immediately before Typing Council acceptance of the PEP.

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📚 Documentation preview 📚: https://pep-previews--4736.org.readthedocs.build/