Do some cheap fuzzy parsing to detect JSON files not named .json. (re. #888112)

class JSONFile(File):

    FILE_EXTENSION_SUFFIX = '.json'

    @classmethod

    def recognizes(cls, file):

        if not super().recognizes(file):

        with open(file.path) as f:

            # Try fuzzy matching for JSON files

            if not file.name.endswith('.json') and \

                    file.magic_file_type.startswith('ASCII text'):

                if '{' not in f.read(10):

                    return False

                f.seek(0)

        with open(file.path) as f:

            try:

                file.parsed = json.load(

                    f,