Enable ESLint as formatter (#87)

* Enable ESLint as formatter

I was working on a different computer today, and the formatting on save did not work out of the box for me.

I had to manually enable this setting, most people have it probably but explicitly enabling it for this project makes it easier for contributors.

* Update settings.json

.vscode/settings.json

@@ -1,3 +1,6 @@
 {
-	"editor.defaultFormatter": "dbaeumer.vscode-eslint"
+	"editor.defaultFormatter": "dbaeumer.vscode-eslint",
+	"editor.codeActionsOnSave": {
+		"source.fixAll.eslint": "explicit"
+	}
 }