enhancement: Delete all multiposts (rather than just after the third posting)

[GabeMillikan]

• Current behavior: send a warning about the second post, delete the third and subsequent postings
• Proposed behavior: delete the second and subsequent postings

"public" discussion: https://discord.com/channels/238956364729155585/892125731600101406/1256106776986652693 contributor discussion: https://discord.com/channels/238956364729155585/1040360228388098159/1256324629723877487