Allow whitespace characters within component regex

[Archmonger]

Description

I realized some handlebars formatters will add indentation and newlines. Therefore, I've made the component regex a bit more robust to handle those situations.

Checklist:

Please update this checklist as you complete each item:

• Tests have been included for all bug fixes or added functionality.
• The changelog.rst has been updated with any significant changes, if necessary.
• GitHub Issues which may be closed by this PR have been linked.

[rmorshea]

In usages of the regex pattern you can use pattern.match(...).group(group_name) instead of grabbing them by index.

[Archmonger]

I believe pattern.match(...).group(group_name) only works with single objects. To "find all" I needed to use finditer and groupdict.

I don't believe I'm using the index anywhere anymore.