Adds :emoji: syntax support to VS Code's built-in Markdown preview

Features

This extension adds support for :emoji: syntax to VS Code's built-in markdown preview.

It extends these emoticons by providing the following list of additional marks:

These are used when performing review by checklists, typically as follows:

Requirement ID	PASS	Complete	Testable	Compatible	Unambiguous
REQ-1	:+:	:V:	:V:	:V:	:+:
REQ-2	:X:	:V:	:X:	:~:	:V:
REQ-3	:V:	:V:	:V:	:~:	:V:
REQ-4	:.:	:.:	:.:	:.:	:.:

:-)

which has the benefit of

clearly signaling red crosses and bells in the Markdown Preview, to show where work is needed;
having more options than a checkbox, which cannot capture the review pass/fail state;
be exactly equally long regardless of state;
does not break existing Markdown syntax.

This extension does not allow the box in the Markdown Preview to be clicked. Updating the box must be done in the editor.

Markdown Emoji + Review