PEP 748: Fix auto-numbering syntax for RST

[elatt]

Parts of this PEP reference sections of the numbered lists and it makes it more challenging to read when the numbered list isn't actually displayed correctly 😉 .

• 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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📚 Documentation preview 📚: https://pep-previews--4340.org.readthedocs.build/

[ghost]

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