docs: fix style guide audit findings

[brendanjryan]

Summary

• Remove the variant code-group restriction from the docs agent guidance
• Normalize MPP terminology capitalization for Challenge, Credential, and Receipt across docs prose
• Fix multi-line highlight markers, skipped heading levels, and reserved-funds/specification wording

Motivation

Keep the documentation aligned with the current style guide and remove a rule that no longer matches accepted docs patterns.

Key design considerations

• Preserve code identifiers and parameter names while updating surrounding prose
• Keep escrow only where it documents an actual code identifier
• Use singular IETF Specification wording consistently

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Project	Deployment	Actions	Updated (UTC)
mpp	Ready	Preview, Comment	Jun 24, 2026 11:16pm

[chatgpt-codex-connector]

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[chatgpt-codex-connector]

Use the actual WebSocket receipt discriminator

In the WebSocket transport docs, the protocol table and example messages above still define the discriminator as payment-receipt, but this diagram now renders payment-Receipt (and the color key was changed the same way). Readers implementing the flow from the sequence diagram would send or listen for a discriminator that doesn't match the documented message protocol, so keep the diagram label lower-case.

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