@canner/slate-icon-codeBlock

Icon:

import CodeBlock from "@canner/slate-icon-codeBlock";

Plugin:

import { CodeBlockPlugin } from "@canner/slate-icon-codeBlock";

Also you'll need to add these two plugins to make code blocks work:

import EditPrism from "slate-prism";
import EditCode from "slate-edit-code";

plugins = [
  EditPrism({
    onlyIn: node => node.type === "code_block",
    getSyntax: node => node.data.get("syntax")
  }),
  EditCode({
    onlyIn: node => node.type === "code_block"
  })
];