Update body preprocessing

[summera]

No description provided.

[summera]

As you can see in the tests this helps with situations where you have a reply directly above a hyphenated line, i.e.,

Reply directly above hyphen line
----------------------------------------------
A bunch of stuff below hyphen.

[rothsa]

👍

[summera]

@technoweenie checking in on these and the other open PRs

[krzysiek1507]

Sir @tenderlove would you be so kind to take a look at this? ;)