ISSUE-8853: [website] The REST API links in the doc body do not work now

[sijie]

Original Issue: apache#8853

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Describe the bug
When I click the REST API links in the doc body, they do not work properly at the moment. The following two links are just examples.

To Reproduce
Steps to reproduce the behavior:

1. Go to http://pulsar.apache.org/docs/en/admin-api-topics/#list-of-topics
2. Click the link in the REST API tabs.
3. They navigates to a blank page. Shown as follows:
   

Expected behavior
It should navigate to https://pulsar.incubator.apache.org/admin-rest-api/?version=2.7.0&apiversion=v2

Desktop (please complete the following information):

• OS: [ iOS]

Additional context
If I click "Admin Rest API" header directly, it works https://pulsar.incubator.apache.org/admin-rest-api/?version=2.7.0&apiversion=v2

[Jennifer88huang-zz]

Discussed with @tuteng, we can think ways to add version variable in those commands.