Remove a mapping for lhs.

import { Denops } from "../mod.ts";
import * as mapping from "../mapping/mod.ts";

export async function main(denops: Denops): Promise<void> {
  await mapping.map(denops, "<Plug>(test-denops-std)", "Hello");
  await mapping.map(denops, "<Plug>(test-denops-std)", "Hello", {
    mode: "i",
  });

  await mapping.unmap(denops, "<Plug>(test-denops-std)");
  await mapping.unmap(denops, "<Plug>(test-denops-std)", {
    mode: "i",
  });
}

Users can specify multiple mode value like:

import { Denops } from "../mod.ts";
import * as mapping from "../mapping/mod.ts";

export async function main(denops: Denops): Promise<void> {
  await mapping.map(denops, "<Plug>(test-denops-std)", "Hello", {
    mode: ["n", "i", "x"],
  });

  await mapping.unmap(denops, "<Plug>(test-denops-std)", {
    mode: ["n", "i", "x"],
  });
}