Resolve bad YAML output display in the API

[KevinCawley]

Code Sample, a copy-pastable example if possible

YAMLLoader.add_constructor("!quantity", YAMLLoader.construct_quantity)
YAMLLoader.add_implicit_resolver(
    "!quantity", MockRegexPattern(quantity_from_str), None
)
YAMLLoader.add_implicit_resolver(
    "tag:yaml.org,2002:float", MockRegexPattern(float), None
)
YAMLLoader.add_constructor(
    yaml.resolver.BaseResolver.DEFAULT_MAPPING_TAG,
    YAMLLoader.mapping_constructor,

Problem description

This code is from https://github.com/tardis-sn/tardis/blob/master/tardis/io/util.py, and displays in https://tardis-sn.github.io/tardis/api/tardis.io.util.html

This is causing two large text walls of YAML code to be generated when docs are compiled. This code needs to be corrected so this text wall is not present. It may be an issue with the YAML and what it is loading, or it may be something else.