Update Checks for String in Messages 🧹

[jameshughes89]

As @twentylemon mentioned offline, it is possible to string away markdown and clean up the message contents before doing the search. In most cases this will have no real impact, but it will clean things up nonetheless.

An example where this would help is "This is a string with Tucker _Carlson_ in it" since Tucker _Carlson_ != Tucker Carlson. This way duckbot would still correct the message despite the markup.

https://discordpy.readthedocs.io/en/stable/api.html#discord.utils.remove_markdown
https://discordpy.readthedocs.io/en/stable/api.html#discord.Message.clean_content