Visiting `/docs` results `/docs.html` then 404 if `base` is set as `/docs/`

Describe the bug

Reproduction

https://github.com/JounQin/test/tree/vitepress

yarn docs:build --base /docs/ && yarn docs:serve --base /docs/

Expected behavior

http://localhost:8000/docs (Without ending slash) should work same as http://localhost:8000/docs/ (With ending slash)

System Info

System:
    OS: macOS 13.0
    CPU: (10) arm64 Apple M1 Max
    Memory: 17.64 GB / 64.00 GB
    Shell: 5.8.1 - /bin/zsh
  Binaries:
    Node: 16.15.1 - ~/Library/Caches/fnm_multishells/3706_1656066380637/bin/node
    Yarn: 1.22.19 - ~/Library/Caches/fnm_multishells/3706_1656066380637/bin/yarn
    npm: 8.13.1 - ~/Library/Caches/fnm_multishells/3706_1656066380637/bin/npm
  Browsers:
    Chrome: 103.0.5060.53
    Firefox: 101.0.1
    Safari: 16.0
  npmPackages:
    vitepress: ^1.0.0-alpha.4 => 1.0.0-alpha.4

Additional context

No response

Validations

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• Read the docs.
• Check that there isn’t already an issue that reports the same bug to avoid creating a duplicate.

[staghouse]

Just to add some color here, VuePress handles this the way to OP is requesting. Leaving out the trailing slash resolves the url to directory index.html which does make sense to me - the path should resolve to a usable path which is the trailing slash.

This is probably more particularly important for nested documentation pages like /docs/something/index.md. When leaving out the trailing slash it resolves to /docs/something.html which would never be a built path in this case.

[ranqiangjun]

BTW, the extra .html appended to /docs as /docs.html on the screenshot happens with cleanUrls: "off"