Fixes a giant non-exhaustive switch warning in `UseInvItem`:
```
../Source/inv.cpp: In function ‘bool devilution::UseInvItem(int, int)’:
../Source/inv.cpp:2131:9: warning: enumeration value ‘IDI_GOLD’ not handled in switch [-Wswitch]
2131 | switch (item->IDidx) {
| ^
../Source/inv.cpp:2131:9: warning: enumeration value ‘IDI_WARRIOR’ not handled in switch [-Wswitch]
../Source/inv.cpp:2131:9: warning: enumeration value ‘IDI_WARRSHLD’ not handled in switch [-Wswitch]
../Source/inv.cpp:2131:9: warning: enumeration value ‘IDI_WARRCLUB’ not handled in switch [-Wswitch]
...
```
This documents the chosen LCG parameters and the default mapping function used in random number generation.
GetLCGEngineState() is a helper needed for testing because AdvanceRndSeed combines a distribution with a call to progress the engine. I'll split those eventually but this at least shows the current behaviour and should flag any bugs introduced by future changes.
It was documented as if this stored a seed in the previous LCG cycle but it actually stored the initial seed for the current cycle. This value is never used.
Given the program already lets the destructors get called naturally there's no need to explicitly call this function. Even if it was desirable to re-init the font data the old instances will be destroyed when the new instance is assigned to the optional.
Disabled by default because of these known issues:
1. When clicking on inventory item, it briefly appears a bit shifted (in the wrong coordinates).
This issue can happen with software cursor as well, but is a lot more
obvious with the hardware cursor.
2. Cursor is scaled with nearest-neighbour scaling, which may look a bit different from
how the rest of the graphics are scaled.
See also previous attempt: https://github.com/diasurgical/devilutionX/pull/955 by @viciious
Co-authored-by: Victor Luchits <vluchits@gmail.com>