Reduces the need for the compiler to duplicate this code, by about
100KB executable size.

ToString didn't have a constexpr if statement where needed.
Canonicalize missed an else, causing unreachable code error on MSVC.

Reduces compile times a tad on clang.

This particular setVisible function is unnecessary.
It also has horrible runtime performance, so much that it consumed maybe
80% of the time used to create a widget.

ConfigurationShared::Widget needs to be created with a builder. This
would avoid some duplicated code.

Using typeid without including typeinfo first produces an ill-formed program.

Clicking the slider without directly interacting with the slider handle would
change the value, but not trigger the restore button.

Explain why we need to do things differently at times, to serve as a
reference.

Groups graphics audio and system settings together in a way that
reflects the frontend. This also just conceptually groups them more
nicely than they were.

Also adds a couple characters that denotes the state of the setting.
M for modified, or not default.
C for custom, in context of per-game settings.

Gives every option of the enums a string literal via a macro.

Reduces code bloat a good bit by moving code specific to each sub widget
to their own functions.

Starting with combobox

Putting code specific to the sub-widget in their own function.

Dark theme mandates a 100px minimum width for QAbstractButton, even
though this is not desired here.

Odd issue happens that dragging the cpu or system tabs in custom configs
would cause the window to take up the entire verticle space of the
screen.

Makes comboboxes always correspond to the value of the setting they're
modifying.