Composer messages show literal backslashes before list-like lines #223

Shift+Enter in the composer inserts a hard break, which serializes as a backslash before the newline. When the next line starts like a block (- , 1. , > , # , ===), markdown lets that block interrupt the paragraph, so the break's trailing backslash ends up as literal text in the rendered message (and every list item ends in \).

Repro: type not comprehensive:, Shift+Enter twice, then - .env*, Shift+Enter, - node_modules, and send.

Observed while dogfooding (#5).