Syntax highlight doesn't work for .service.backup file

[lansman]

I've added .service.backup file extension but it doesn't work

It seems your extension takes only the last part of file as extension: my-pretty-file.service.backup and so the extension must have 1 dot only. This is an unnecessary restriction.

Solution: extension detection should work like fileName.EndsWith() so no matter how many dots inside

Details

[rob3c]

You can add this to the vscode settings.json file to get it to work:

{
  "files.associations": {
    "*.service.backup": "systemd-unit-file"
  }
}