Fixing broken documentation links in API exceptions

[SamWheating]

A user on Slack pointed out that the docs URL returned in a 403 API response was broken.

According to the user's report, the 403 response looked like this:

{
    "detail": null,
    "status": 403,
    "title": "Forbidden",
    "type": "https://airflow.apache.org/docs/2.0.0/stable-rest-api-ref.html#section/Errors/PermissionDenied"
}

A quick look into the source and it appears that this reference does in fact point to a nonexistent page.

Before:
https://airflow.apache.org/docs/2.0.0/stable-rest-api-ref.html#section/Errors/PermissionDenied

After:
https://airflow.apache.org/docs/apache-airflow/2.0.0/stable-rest-api-ref.html#section/Errors/PermissionDenied

---

^ Add meaningful description above

Read the Pull Request Guidelines for more information.
In case of fundamental code change, Airflow Improvement Proposal (AIP) is needed.
In case of a new dependency, check compliance with the ASF 3rd Party License Policy.
In case of backwards incompatible changes please leave a note in UPDATING.md.

[SamWheating]

I also found this link in the deprecation headers for the experimental API which appears to be broken.

airflow/airflow/www/api/experimental/endpoints.py

Line 62 in 70290b9

doc_url = get_docs_url("stable-rest-api/migration.html")

However, I don't know what the correct link should be here. Thoughts?

update: It looks like its a reference to this page, which have since been removed.

[mik-laj]

However, I don't know what the correct link should be here. Thoughts?

https://airflow.apache.org/docs/apache-airflow/stable/upgrading-to-2.html#migration-guide-from-experimental-api-to-stable-api-v1

[ryanahamilton]

Sorry I missed this PR earlier, but I believe most of these issues were resolved in #13250 and #14080. The issue in endpoints.py still persists, so you could go ahead with that after rebasing.

[github-actions]

This pull request has been automatically marked as stale because it has not had recent activity. It will be closed in 5 days if no further activity occurs. Thank you for your contributions.

[ryanahamilton]

@SamWheating if you don't mind rebasing this (and then pinging me), I can get it merged in.

[SamWheating]

@SamWheating if you don't mind rebasing this (and then pinging me), I can get it merged in.

@ryanahamilton done ✅

[github-actions]

The PR is likely OK to be merged with just subset of tests for default Python and Database versions without running the full matrix of tests, because it does not modify the core of Airflow. If the committers decide that the full tests matrix is needed, they will add the label 'full tests needed'. Then you should rebase to the latest master or amend the last commit of the PR, and push it with --force-with-lease.