feature: Make files in `diagnostics` use `TroubleFileName` color

[GrzegorzKozub]

Did you check the docs?

• [X] I have read all the trouble.nvim docs

Is your feature request related to a problem? Please describe.

Inconsistent highlighting of files across different Trouble views.

Describe the solution you'd like

Would it be possible to highlight file names in diagnostics with TroubleFileName, similar to symbols? Currently they seem to be highlighted by TroubleNormal.

Describe alternatives you've considered

Changing TroubleNormal helps but also changes the color of the diagnostic messages in Trouble window so it's not ideal.

Additional context

No response

[GrzegorzKozub]

Thank you 😃