feat: add the externalUrlRegex param for Algolia

[andrewgolovanov]

• What kind of change does this PR introduce? (Bug fix, feature, docs update, ...)
  Docs update: This pull request adds the externalUrlRegex param for Algolia.
• What is the current behavior? (You can also link to an open issue here)
  When you go to a page from the documentation search, we get to a page that does not exist
• What is the new behavior (if this is a feature change)?
  This option allows for window.location instead of history.push. Which solves the problem with links for API documentation. You can find more about this here
• Other information:
  N/A