We ignore other types based on these assumptions:
1) It doesn't make sense to show variable identifiers, which may refer to (for example) module-private values that should not be documented.
2) If we tried to capture objects and arrays, we would have to iterate over them to see if they contain any variable identifiers, which would be a pain (and potentially confusing: "Why do some objects appear in the docs but not others?")
3) Most developers will not define complex default values in a function definition.
4) In many cases, object and array default values will be `{}` and `[]`, respectively, and usually those don't merit documentation.
