online help is no longer accessible

[erwindon]

Describe the bug
Using menu item "Online reference for 'xxx'" shows a list of URLs.
These seem to be outdated.

To Reproduce
Steps to reproduce the behaviour:

1. Go to >_
2. Fill command field with test.ping
3. Click on `Online reference for 'test.ping' in the documentation dropdown
4. Scroll down to '....'
5. See error (all 4 links result in "Page not found" (404)

Expected behaviour
These links should point to

Screenshots

Additional context
clickable version of the screenshot:

Documentation for 'test.ping':
Salt Module Reference
All 'execution' modules
Module 'test'
Function-name 'ping' cannot be verified here. We'll just assume it actually exists. The link below might not work.
Function 'test.ping'

[erwindon]

analysis:
documentation has moved from docs.saltstack.com to docs.saltproject.io.
(but structure is the same)

[erwindon]

solution:
adjust hostname in all URLs (too much work to make it a constant)