GraphQL descriptions that are single-quoted, all on one line, or not at the top-level are not highlighted correctly

[xenomachina]

Name of the lexer GraphQL

Code sample

"""
InputOne's description (works)
"""
input InputOne {
  """
  id's description (doesn't work)
  """
  id: Int!
}

"""InputTwo's description (doesn't work)"""
input InputTwo {
  """id's description (doesn't work)"""
  id: Int!
}

"InputThree's description (doesn't work)"
input InputThree {
  "id's description (doesn't work)"
  id: Int!
}

Additional context

It looks like the handling of GraphQL descriptions is too restrictive. The example above can be tried on the Rouge home page's GraphQL tester. All of the quoted descriptions should highlight as descriptions, but only one is correctly identified as a description. It looks like there are possibly 3 separate sub-issues:

• GraphQL descriptions are "StringValues", and a StringValue can use a pair of double-quotes, not just a pair of triple-double-quotes (""").
• A triple-quoted StringValue can be all on one line. eg: """hello, world!"""
• A description can appear not only before a top-level definition, but also before nested definitions, like fields.