SourceSetFileDialog visual & keyboard / mouse interaction improvements

[Traben-0]

Description

refactor SourceSets and the list for the PreprocessorJumpAction:

• corrects list ordering
• support override files from versions/<version>/src/
• remove redundant full path from the list string
• layout list cells into nicer columns
• add simple "key" to streamline keyboard searching further
• add indicators for main & override files

also:

• upon filtering the list via search, it auto selects the first result for keyboard navigation streamlining
• focused the search field upon opening for keyboard navigation streamlining
• allows double clicking a list entry to open it immediately

Related Issue(s)

Fixes #19
partially fixes #18

How to test

use the preprocessor file jump dialogue box

Release Notes

- Added support for override files within `versions/<version>/src/` to the "jump to preprocessed files" action.
- Improved the visual clarity of the list in the "jump to preprocessed files" dialogue window.
- Improved keyboard navigation of the "jump to preprocessed files" dialogue window.
- Allowed double clicking on entries in the "jump to preprocessed files" dialogue window to open the file.
- Fixed sorting of entries in the "jump to preprocessed files" dialogue window.

[Traben-0]

This wasn't particularly made for those issues, one isnt fully addressed

I've just been modifying this for personal use and figured i'd see if the changes were wanted here