Use new Discord markdown support for bot messages (#2726)

* feat: use new markdown feature in new help channel message

* feat(tags): update bullet points to dashes in tags

* feat(tags): add dashes to async libraries list

* feat: update markdown in patreon command

* feat: update markdown in otname command

* feat: update markdown in filter command

* feat: update markdown in voiceverify command

* feat: update markdown in docs command

* feat: update markdown in bigbrother command

* feat: update markdown in talentpool command

Default arguments in Python are evaluated once when the function is defined, not each time the function is called. This means that if you have a mutable default argument and mutate it, you will have mutated that object for all future calls to the function as well.

For example, the following append_one function appends 1 to a list and returns it. foo is set to an empty list by default.

>>> def append_one(foo=[]):
...     foo.append(1)
...     return foo
...

See what happens when we call it a few times:

>>> append_one()
[1]
>>> append_one()
[1, 1]
>>> append_one()
[1, 1, 1]

Each call appends an additional 1 to our list foo. It does not receive a new empty list on each call, it is the same list everytime.

To avoid this problem, you have to create a new object every time the function is called:

>>> def append_one(foo=None):
...     if foo is None:
...         foo = []
...     foo.append(1)
...     return foo
...
>>> append_one()
[1]
>>> append_one()
[1]

Note:

This behavior can be used intentionally to maintain state between calls of a function (eg. when writing a caching function).
This behavior is not unique to mutable objects, all default arguments are evaulated only once when the function is defined.