Pressing a formatting hotkey should toggle that formatting

[ByteOfBrie]

When you format text with a hotkey (ctrl-i for italics) on text that is already formatted, it should clear away existing formatting instead of trying to apply it again.

For example, when pressing ctrl-i repeatedly on the same text, you currently get:

text
*text*
**text**
***text***

instead, I would expect to get:

text
*text*
text
*text*

Notably, this should still work fine when text is already formatted with some other type (i.e., bold):

**text**
***text***
**text**
***text***