[V3 Trivia] Handle smart quotes

[mikeshardmind]

Type

• Bugfix
• Enhancement
• New feature

Description of the changes

Adds a new filter function for substituting out smart-quotes.

Makes trivia use it.

[Twentysix26]

My only nitpick here is that the name of the function looks pretty weird with un being separate and smartquote as a single word. As far as I know the un prefix is never used as a word on its own in English.
I would have went with something like normalize_smart_quotes (replace could work too), which also respects the other function names being plural instead of singular.
In this case the to_filter parameter name should also be renamed since you're not filtering, you are transforming text.

[Tobotimus]

Thanks for this PR 👍