[BUG] Duplicate routes with embedded sidebar

Reproduce the route warning with docusaurus.config.js, sidebar-nil.js, and the nil/reference/test.md structure using Docusaurus 3.x. Trace how the embedded sidebar and generated reference routes are created; done means the site renders without duplicate routes in this configuration.

Issue

The normal flow of configuring and using the plugin results in receiving the following error when using Docusaurus 3.x.

[WARNING] Duplicate routes found!
- Attempting to create page at \nil\reference\json-rpc-api, but a page already exists at this route.
This could lead to non-deterministic routing behavior.

As a result of this error, the entire site fails to render.

Steps to reproduce

docusaurus.config.js:

// @ts-check
// `@type` JSDoc annotations allow editor autocompletion and type checking
// (when paired with `@ts-check`).
// There are various equivalent ways to declare your Docusaurus config.
// See: https://docusaurus.io/docs/api/docusaurus-config

import { themes as prismThemes } from 'prism-react-renderer';

import remarkMath from 'remark-math';
import rehypeKatex from 'rehype-katex';

/** @type {import('@docusaurus/types').Config} */
const config = {
  title: '=nil; Foundation Documentation Portal',
  tagline: '',
  favicon: 'img/nil-logo.png',

  // Set the production url of your site here
  url: 'https://docs.nil.foundation/',
  // Set the /<baseUrl>/ pathname under which your site is served
  // For GitHub pages deployment, it is often '/<projectName>/'
  baseUrl: '/',

  // GitHub pages deployment config.
  // If you aren't using GitHub pages, you don't need these.
  organizationName: '=nil; Foundation', // Usually your GitHub org/user name.
  projectName: 'docs.nil.foundation', // Usually your repo name.

  onBrokenLinks: 'throw',
  onBrokenMarkdownLinks: 'warn',

  // Even if you don't use internationalization, you can use this field to set
  // useful metadata like html lang. For example, if your site is Chinese, you
  // may want to replace "en" with "zh-Hans".
  i18n: {
    defaultLocale: 'en',
    locales: ['en'],
  },

  presets: [
    [
      "@metamask/docusaurus-openrpc/dist/preset",
      /** @type {import('@metamask/docusaurus-openrpc/dist/preset').Options} */
      ({
        docs: {
          path: 'nil',
          routeBasePath: 'nil',
          sidebarPath: require.resolve("./sidebar-nil.js"),
          remarkPlugins: [remarkMath],
          rehypePlugins: [rehypeKatex],
          openrpc: {
            openrpcDocument: "https://metamask.github.io/api-specs/latest/openrpc.json",
            path: "reference",
            sidebarLabel: "JSON-RPC API",
          },
        },
        theme: {
          customCss: require.resolve("./src/css/custom.css"),
        },
      }),
    ],
  ],
  markdown: {
    mermaid: true,
  },
  themes: ['@docusaurus/theme-mermaid'],
  plugins: [
    [
      '@docusaurus/plugin-content-docs',
      {
        id: 'zkllvm',
        path: 'zkllvm',
        routeBasePath: 'zkllvm',
        sidebarPath: './sidebar-zkllvm.js'
      }
    ],
    [
      '@docusaurus/plugin-content-docs',
      {
        id: 'proof-market',
        path: 'proof-market',
        routeBasePath: 'proof-market',
        sidebarPath: './sidebar-proof-market.js'
      }
    ],
    [
      '@docusaurus/plugin-content-docs',
      {
        id: 'crypto3',
        path: 'crypto3',
        routeBasePath: 'crypto3',
        sidebarPath: './sidebar-crypto-3.js'
      }
    ],
  ],
  stylesheets: [
    {
      href: 'https://cdn.jsdelivr.net/npm/[email protected]/dist/katex.min.css',
      type: 'text/css',
      integrity:
        'sha384-odtC+0UGzzFL/6PNoE8rX/SPcQDXBJ+uRepguP4QkPCm2LBxH3FA3y+fKSiJ+AmM',
      crossorigin: 'anonymous',
    },
  ],
  themeConfig:
    /** @type {import('@docusaurus/preset-classic').ThemeConfig} */
    (
      {
        algolia: {
          appId: 'KDQGY81FVN',
          apiKey: '8ad8d801f2775ff3cf8c4433dfe290e4',
          indexName: 'nil',
          contextualSearch: true,
          searchParameters: {},
          searchPagePath: 'search',
          insights: false,
        },
        colorMode: {
          defaultMode: 'dark',
          disableSwitch: true,

        },
        navbar: {
          title: '=nil; Foundation',
          logo: {
            src: 'img/nil-logo.png',
          },
          items: [
            {
              position: 'left',
              label: '=nil;',
              to: '/nil/intro'
            },
            {
              position: 'left',
              label: 'zkLLVM',
              to: '/zkllvm/overview/what-is-zkllvm'

            },
            {
              position: 'left',
              label: 'Proof Market',
              to: '/proof-market/intro'
            },
            {
              position: 'left',
              label: 'Crypto3',
              to: '/crypto3/intro'
            },
          ],
        },
        footer: {
          links: [
            {
              title: 'Community',
              items: [
                {
                  label: 'Discord',
                  to: 'https://discord.gg/KmTAEjbmM3'
                },
                {
                  label: 'GitHub',
                  to: 'https://github.com/nilfoundation'
                },
                {
                  label: 'Telegram',
                  to: 'https://t.me/nilfoundation'
                }
              ],
            }
          ],
          style: 'dark',
          copyright: `Copyright © ${new Date().getFullYear()} =nil; Foundation`,
        },
        prism: {
          defaultLanguage: 'clike',
          theme: prismThemes.vsDark,
          darkTheme: prismThemes.vsDark,
        },
      }),
};

export default config;

sidebar-nil.js:

export default {
    nil: [
        {
            type: 'category',
            label: 'Introduction',
            collapsed: false,
            collapsible: true,
            items: [
                {
                    type: 'doc',
                    label: 'Overview',
                    id: 'intro',
                },
                {
                    type: 'doc',
                    label: 'Thesis',
                    id: 'thesis'
                },
                {
                    type: 'doc',
                    label: 'Principles',
                    id: 'principles'
                }
            ]
        },
        {
            type: 'category',
            label: 'Core concepts',
            collapsed: false,
            collapsible: true,
            items: [
                {
                    type: 'doc',
                    label: 'Accounts',
                    id: 'core-concepts/accounts',
                },
                {
                    type: 'doc',
                    label: 'Transaction lifecycle',
                    id: 'core-concepts/transaction-lifecycle',
                },
                {
                    type: 'doc',
                    label: 'Shards and parallelized execution',
                    id: 'core-concepts/shards-parallel-execution',
                },
                {
                    type: 'doc',
                    label: 'Contract co-location',
                    id: 'core-concepts/contract-co-location',
                },
            ]
        },
        {
            type: 'category',
            label: 'Specification',
            collapsed: true,
            collapsible: true,
            items: [
                {
                    type: 'doc',
                    label: 'Finality',
                    id: 'specification/finality',
                },
                {
                    type: 'doc',
                    label: 'Data availability',
                    id: 'specification/data-availability',
                },
                {
                    type: 'doc',
                    label: 'Sequencing',
                    id: 'specification/sequencing',
                },
            ]
        },

        {
            type: "category",
            label: "Reference",
            link: { type: "generated-index" },
            items: [{ type: "autogenerated", dirName: "reference" }],
        },
    ]


}

File structure:

root
-- nil
    -- reference
        -- test.md

Expected behaviour

The flow for configuring and using the plugin does not cause route duplication.