Document InnerHandler null requirement for DI by bbrandt · Pull Request #1569 · reactiveui/refit

What kind of change does this PR introduce?
docs update

What is the current behavior?
See #1403

What is the new behavior?
Clearly documented

What might this PR break?
documentation only. Helps devs get started more easily with Auth in Refit.

Please check if the PR fulfills these requirements

  • Tests for the changes have been added (for bug fixes / features)
  • Docs have been added / updated (for bug fixes / features)

Other information: