Created attachment 163074 [details]
String not highlighted

SUMMARY

The string in line 4 is not highlighted as such: 

```nix
  programs.firefox = {
    enable = true;
    preferences = {
      "widget.use-xdg-desktop-portal.file-picker" = 1;
      "widget.use-xdg-desktop-portal.mime-handler" = 1;
      "browser.backspace_action" = 0;
    };
  };
```

STEPS TO REPRODUCE
1.  Open file
2.  Paste above content into it
3.  Name it blabla.nix or set file type to Nix
4.  Look at line 4

OBSERVED RESULT

String not highlighted

EXPECTED RESULT

String highlighted as all the other strings 

Operating System: NixOS 23.05
KDE Plasma Version: 5.27.9
KDE Frameworks Version: 5.106.0
Qt Version: 5.15.10
Kernel Version: 6.6.0 (64-bit)
Graphics Platform: X11
Processors: 16 × AMD Ryzen 7 5800U with Radeon Graphics
Memory: 13,5 GiB of RAM
Graphics Processor: AMD Radeon Graphics

ADDITIONAL INFORMATION

See screenshot