Here strings (`<<<`) cause syntax highlight issues with command substitution

[dnicolson]

Prerequisites

• Put an X between the brackets on this line if you have done all of the following:
  • Reproduced the problem in Safe Mode: https://flight-manual.atom.io/hacking-atom/sections/debugging/#using-safe-mode
  • Followed all applicable steps in the debugging guide: https://flight-manual.atom.io/hacking-atom/sections/debugging/
  • Checked the FAQs on the message board for common solutions: https://discuss.atom.io/c/faq
  • Checked that your issue isn't already filed: https://github.com/issues?utf8=✓&q=is%3Aissue+user%3Aatom
  • Checked that there is not already an Atom package that provides the described functionality: https://atom.io/packages

Description

Here strings (<<<) when used with command substitution cause two issues:

• The closing bracket ()) is a different color to the opening one
• The use of backticks (`) results in improper syntax highlighting on the lines below

Steps to Reproduce

Open the following code in Visual Studio Code:

#!/bin/bash

echo one two
cat <<< $(echo one two)
echo one two

echo one two
cat <<< `echo one two`
echo one two

echo one two
cat <<< $(echo one two)
echo one two

Expected behavior:

The syntax highlighting to be like Atom (version https://github.com/atom/language-shellscript/releases/tag/v0.28.2):

Actual behavior:

Visual Studio Code (version 4f8d7bb5cc4d1643674551683df10fe552dd5a6f)

Visual Studio Code is a few commits ahead of Atom, the issue appears to have been introduced in 4f8d7bb.