checks: Add display and other modules root folder as accepted title prefixes

[echoix]

As we can see in #5328, the title "display: fix typos" doesn't fit in our classification regex. I think it is a valid title as it groups changes from different d.* modules, in the display folder.

So, I added that folder, plus other folders containing modules as valid prefixes.
Note that I didn't include "raster" or "vector", as they are already part of another section below, and I didn't check how it would behave, so I'm keeping it safe.

    - title: Libraries and General Functionality
      regexp: '(?:Revert \")?(grass_|lib|TGIS|tgis|raster|vector)[^ ]*: '
      example: 'grass_btree: or lib/btree:'

[wenzeslaus]

That's inconsistent, isn't it?

[echoix]

I think it was originally used when "raster" or "vector" work was for the C library, not modules. That's my interpretation. So I didn't want to blindly change the interpretation/classification of older PR titles in 8.5

[wenzeslaus]

The purpose is to help sort out release notes whichare meant for users (of any kind). Linting fixes should probably be checks or qc rather than library or modules.