Tap generate docs: anyOf support and improved error messages

[luandy64]

Summary

This PR adds the following improvements to tap-generate-docs:

• Add a helpful error message when we encounter an array with no items field
  • This mirrors the check we do for objects and properties
• Add support for anyOf in schemas
• Add a comment block that can be used to debug the script

I highly recommend hiding whitespace changes while reviewing the PR.

anyOf design

convert-multiary-type already supports schemas with a array for the type of the field.

docs/scripts/tap-generate-docs/test/tap_generate_docs_test.clj

Lines 243 to 247 in cb6bbe1

	["a_date" {"type" ["null" "string" "integer"]
	"format" "date-time"}]
	{"name" "a_date"
	"type" "date-time, integer"
	"description" ""}

So to support anyOf, this PR merges all of the maps in the anyOf array and lets the the existing functions handle the parsing.

Notice the test case I added to convert-multiary-type-tests mirrors the test case right above it (except mine uses anyOf) and the outputs are expected to be the same.

Outstanding questions

• Is there a more clojure-y way to write maybe-remove-anyOf?
• Is there a function that does the merge I want to do in remove-anyOf without my anonymous function passed to merge-with?

[dmosorast]

The general gist sounds good, and I trust that the tests prove that.

I'm concerned about the case where the type is something like "anyOf": [{"type": "string"}, {"type": "string", "format": "date-time"}], since merging them seems to remove the notion that this is a special case where the dates can return as invalid, in which case we type them as strings.