Monarch definition of shell language breaks bash syntax highlighting with some command substitutions

monaco-editor version: 0.20.0 (assuming that's the version on the playground) Browser: Chrome OS: Windows Playground code that reproduces the issue:

monaco.editor.create(document.getElementById("container"), {
	value: "function sample-highlight() {\n  echo \"the echo command looks different from this quoted text,\"\n  loc_formatted=$(echo \"WORD\" | awk \'{print tolower($0)}\')\n  echo \"this echo command is the same color as this text\"\n}\n\nfunction still() {\n  echo \"the issue extends out of the scope of that function\"\n}\n",
	language: "shell"
});

I ran into an issue that can be reproduced by displaying the following bash in the Monaco editor, but not VS code:

function sample-highlight() {
  echo "the echo command looks different from this quoted text,"
  loc_formatted=$(echo "WORD" | awk '{print tolower($0)}')
  echo "this echo command SHOULD look different from this text"
}

function still() {
  echo "the issue extends out of the scope of that function"
}

If typed into Visual Studio Code, version info below,

Version: 1.42.1 (system setup)
Commit: c47d83b293181d9be64f27ff093689e8e7aed054
Date: 2020-02-11T14:45:59.656Z
Electron: 6.1.6
Chrome: 76.0.3809.146
Node.js: 12.4.0
V8: 7.6.303.31-electron.0
OS: Windows_NT x64 10.0.18363

that text renders correctly, like so:

If you create a file called sample.sh in the visual studio code playground (version info below),

Version: 1.46.0-insider
Commit: b26e0bcf39c1b8faaf770265391b5a387d1d9172
Date: 2020-05-26T15:43:08.115Z (product build time)
Browser: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/83.0.4103.61 Safari/537.36

and add bash in question, it will again render correctly:

However, if navigate to the monaco homepage at https://microsoft.github.io/monaco-editor/index.html and select shell, then paste in the sample functions, the syntax highlighting breaks

If you visit the Monaco playground and add this command:

monaco.editor.create(document.getElementById("container"), {
	value: "function sample-highlight() {\n  echo \"the echo command looks different from this quoted text,\"\n  loc_formatted=$(echo \"WORD\" | awk \'{print tolower($0)}\')\n  echo \"this echo command is the same color as this text\"\n}\n\nfunction still() {\n  echo \"the issue extends out of the scope of that function\"\n}\n",
	language: "shell"
});

after clicking "run" you get an instance of incorrect highlighting on the right-hand side:

I discovered this issue while using Azure DevOps, where it shows up if you edit a file with a .sh ending:

I've been working on an MS-internal repo full of bash lately, and this bug has been making it a little tricky to review pull requests there.