Some URLs in the Rich_Text_Editor contain _
characters, but haven't been converted
to links yet. For example, https://www.example.com/a_test_of_links.
We should preserve the underscores _without escaping them_ to prevent the links from breaking.
This should also correctly handle unicode characters. For example, punctuationβ―_requires escapes_, but ππππππ½_π π₯ππ―ππ π±π’π―π°_and_897_numbers_πon_'t.
_Note_ that what [_causes_] a `_` to create italics_ seems to depend only on the character before and an escape at the _beginning_ seems to be sufficient.
_s also don't need escapes if _ followed _ by a _space.