Some todos

[hoodmane]

• Update to typedoc v0.23
• Update to typedoc v0.25
• Improve error message when typedoc fails
• Internal xrefs in rendered types
• External xrefs in rendered types (e.g., to MDN, typescript, or node docs)
• async prefix for async functions
• deprecated tag
• examples
• stability tags? (e.g., @experimental)
• parameter destructuring
• type rendering for the rest of the reflection types
• unit tests for function renderer
• unit tests for class/attribute renderers
• Interfaces should probably say "interface X" instead of "class X"
• Get rid of unittest.TestCase