fix(v2): Fix double trailingSlash in sitemap.xml

[ntbosscher]

Fix issue where when trailingSlash option is enabled, routes that already end in a / are shown with double slash at the end.

Motivation

Some of my routes show in sitemap.xml without a trailing slash, so I use trailingSlash to make them all consistent. However, some of my paths (e.g. /docs/ created by getting_started.md) already have a trailing slash. Currently /docs/ will be rendered as /docs// in the sitemap which isn't correct. This fix prevents that trailing double slash when the trailingSlash option is enabled.

Have you read the Contributing Guidelines on pull requests?

Yes

Test Plan

1. Update your docusaurus.config.js to enable sitemap's trailingSlash option

plugins: [
    [
      '@docusaurus/plugin-sitemap',
      {
        id: 'plugin-sitemap-default',
        trailingSlash: true,
      },
    ],
  ],

2. Create a page in /docs with slug: /
3. Generate the sitemap by creating an optimized production build
4. Verify that the build/sitemap.xml entry generated for /docs/ doesn't have a trailing slash

Related PRs

N/A

[github-actions]

Size Change: -2 B (0%)

Total Size: 26.7 kB

ℹ️ View Unchanged

Filename	Size	Change
website/build/blog/2017/12/14/introducing-docusaurus/index.html	20.7 kB	-2 B (0%)
website/build/docs/introduction/index.html	180 B	0 B
website/build/index.html	5.82 kB	0 B

_{compressed-size-action}

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[github-actions]

⚡️ Lighthouse report for the changes in this PR:

Category	Score
🟠 Performance	87
🟢 Accessibility	99
🟢 Best practices	100
🟢 SEO	100
🟢 PWA	95

Lighthouse ran on https://deploy-preview-4004--docusaurus-2.netlify.app/classic/

[slorber]

LGTM, thanks 👍

[slorber]

weird, this PR has a prettier formatting issue that was not catched by the CI

Will be fixed by #4005

Also replaced code by our addTrailingSlash util (it does not add duplicate trailing slashes)