Jira does not have knowledge-base connectors for anything other than Confluence.
You can use any Confluence - a server/dc install or a cloud confluence on a different site, but there's nothing for other things you might have a knowledge base beyond being able to link to a url where the other system is.
I understand a couple of people are working on connectors for other systems (so that Jira can search them and recommend articles when people are asking questions), but those will, of course, be done by type of system.
