$ts-webpack-watch is generated by yo in tasks.json but isn't recognised by VsCode

[geoidesic]

I ran:

npm i -g yo generate-code;
yo code

Which generated this tasks.json file:

// See https://go.microsoft.com/fwlink/?LinkId=733558
// for the documentation about the tasks.json format
{
	"version": "2.0.0",
	"tasks": [
		{
			"type": "npm",
			"script": "watch",
			"problemMatcher": "$ts-webpack-watch",
			"isBackground": true,
			"presentation": {
				"reveal": "never",
				"group": "watchers"
			},
			"group": {
				"kind": "build",
				"isDefault": true
			},
		},
		{
			"type": "npm",
			"script": "watch-tests",
			"problemMatcher": "$tsc-watch",
			"isBackground": true,
			"presentation": {
				"reveal": "never",
				"group": "watchers"
			},
			"group": "build"
		},
		{
			"label": "tasks: watch-tests",
			"dependsOn": [
				"npm: watch",
				"npm: watch-tests"
			],
			"problemMatcher": []
		}
	]
}

But VsCode Problems reports:

[{
	"resource": "/Users/blah/blah/.vscode/tasks.json",
	"owner": "_generated_diagnostic_collection_name_#2",
	"code": "1",
	"severity": 4,
	"message": "Unrecognized problem matcher. Is the extension that contributes this problem matcher installed?",
	"startLineNumber": 9,
	"startColumn": 22,
	"endLineNumber": 9,
	"endColumn": 41
}]

When I run "Start Debugging", I get this alert

[aeschli]

You also need to install the recommended extension "amodio.tsl-problem-matcher"