StarWarsSchema type descriptions are null in Introspection docs

[reillylm]

We're currently specifying descriptions in the StarWarsSchema using comments:

graphql.github.io/src/components/Marked/swapiSchema.tsx

Lines 112 to 113 in 51db38b

	# An autonomous mechanical character in the Star Wars universe
	type Droid implements Character {

...which is causing them to resolve as null when we run introspection queries, like in this example on the Introspection docs page:

The newer versions of the spec outline that descriptions should use a BlockString like this:

"""
An autonomous mechanical character in the Star Wars universe
"""
type Droid implements Character {}

Here's with a BlockString description for Droid instead:

Looks like, alternatively, we could specify commentDescriptions in our invocation of makeExecutableSchema, but we might as well make our schema consistent with the current way of specifying descriptions in the spec.

I can open a PR for this change if it sounds good.