import { prompt_setprompt } from "https://deno.land/x/denops_std@v6.4.0/function/mod.ts";
Set prompt for buffer {buf} to {text}. You most likely want {text} to end in a space. The result is only visible if {buf} has 'buftype' set to "prompt". Example:
call prompt_setprompt(bufnr(), 'command: ')
Can also be used as a method:
GetBuffer()->prompt_setprompt('command: ')
only available when compiled with the +channel feature