Hash navigation breaks in 3.4.0 with some plugins

[razzeee]

Have you read the Contributing Guidelines on issues?

• I have read the Contributing Guidelines on issues.

Prerequisites

• I'm using the latest version of Docusaurus.
• I have tried the npm run clear or yarn clear command.
• I have tried rm -rf node_modules yarn.lock package-lock.json and re-installing packages.
• I have tried creating a repro with https://new.docusaurus.io.
• I have read the console error message carefully (if applicable).

Description

We're using https://github.com/gabrielcsapo/docusaurus-plugin-search-local and updating to 3.4.0 changes the links the search produces.

They end up in a duplicated format like https://docs.flathub.org/docs/for-app-authors/linter/docs/for-app-authors/linter#linter-errors instead of https://docs.flathub.org/docs/for-app-authors/linter#linter-errors

See
gabrielcsapo/docusaurus-plugin-search-local#82

I couldn't spot a hint at a behaviour change in the changelog, but I might have overlooked it or this is a regression.

The new hashnav changes are opt in so far it seems?

Reproducible demo

flathub-infra/documentation#339

Steps to reproduce

1. run yarn
2. yarn build
3. yarn serve
4. Go to the page
5. Search for linter error
6. Click the first result

Expected behavior

It should route you to the correct path and scroll down to the hash navigation

Actual behavior

You get a 404

Your environment

• Public source code: build(deps): bump the docusaurus group with 5 updates flathub-infra/documentation#339
• Public site URL: https://docs.flathub.org/
• Docusaurus version used: 3.4.0
• Environment name and version (e.g. Chrome 89, Node.js 16.4): Seems unrelated, can repro in multiple envs
• Operating system and version (e.g. Ubuntu 20.04.2 LTS): Seems unrelated, can repro in multiple envs

Self-service

• I'd be willing to fix this bug myself.

[slorber]

See my answer here: gabrielcsapo/docusaurus-plugin-search-local#82 (comment)

Although we have our responsibility, Docusaurus core works fine and this is a third-party plugin bug.