Function render_entry_block 

pub fn render_entry_block(input: &RenderInput<'_>) -> String

Render a single entry block as markdown.

Output ends with a trailing blank line so subsequent entries appended to the same file don’t run together. Output is fully deterministic given the input; no global state is consulted.

Field order in the output is fixed: ## date — title, then **why:**, then optionally **rejected:**, **risk:**, **tags:**.