Code inside tabbed code block may turn into emoji

Issue Summary

When code is added to a tabbed code block in a pull request comment, the code may be incorrectly turned into emoji.

Steps to Reproduce

1. Add the following comment in a Pull Request:

   REGULAR TEXT
   
   	if (foo == 8)
   
   REGULAR TEXT
   

1. Notice that "8)" is turned into the emoji:
   

Expected Results

"8)" should not be turned into emoji.

Actual Results

• "8)" is turned into emoji.
• It cannot be escaped with a backslash because the backslash ends up being displayed:

Workaround

Use backticks (```) for encapsulating the code block, like this:

REGULAR TEXT
```
	if (foo == 8)
```
REGULAR TEXT

  Alternatively, use 4 spaces for the indentation rather than a tab character.