Function write_destination 

pub fn write_destination(target: &Utf8Path, entry: &Entry) -> Result<()>

Land one entry: the whole file through the temp-plus-rename writer, or the block spliced into its document and the whole document rewritten the same way.

Errors

Any write failure; the destination then holds what it held. An unspliceable hook file surfaces as an error here only as a backstop — hooks_splice_refusal is the check a verb runs before any write.