Markdown: munges github emoji strings when along-side italics

[bradzacher]

trafficstars

Prettier 2.3.2 Playground link

--parser markdown

Input:

:stop_sign: ***(new)***
:stop_sign: **_(new)_**

Output:

:stop*sign: ***(new)***
:stop_sign: \*\**(new)\_\*\*

Expected behavior:

:stop_sign: **_(new)_**
:stop_sign: **_(new)_**

Prettier assumes that the _ in the emoji string is an italic marker, so then it does some weird stuff with it.

[myknbani]

I can confirm this as well:

[:point_up_2: _credits_](https://stackoverflow.com/a/65831302/2310634)

[codingluke]

Same on my side

:japanese_goblin: *Fasnachtsferien*

is "corrected" to

:japanese_goblin: _Fasnachtsferien_

which kills the emoji 😢

[kachkaev]

@codingluke convering * to _ for italics is expected behavior. The same applies to __ converting to ** for bold.

Prettier 2.8.4 Playground link

--parser markdown

Input:

*italics*
_italics_
**bold**
__bold__

:japanese_goblin: *Fasnachtsferien*

Output:

_italics_
_italics_
**bold**
**bold**

:japanese_goblin: _Fasnachtsferien_

[tillig]

This still is an issue in v2.8.8 for emoji that have more than one underscore:

Input:

:hammer_and_wrench: That emoji has _multiple underscores_ in it and causes problems.

Output:

:hammer_and_wrench: That emoji has \_multiple underscores* in it and causes problems.