Support arbitrary keys in objects by falling back to the functional typed dict definition

[TheLartians]

For example, the type

/** This is A */
export type A = {
  /** this is foo.bar */
  "foo.bar": string,
  /** this is a/b */
  "a/b": number,
  "undocumented": string,
}

is transpiled to

from typing import TypedDict

A = TypedDict("A", {
  "foo.bar": str,
  "a/b": float,
  "undocumented": str
})
"""
This is A
## Entries
"foo.bar": this is foo.bar
"a/b": this is a/b
"""