Remapping: Documentation and defaults update + add option to use a unified config (#2302)

* Add a toggle to use unified or per-game configs, and add a deadzone example to the default config

* Add a checkbox to toggle config type

* clang

src/qt_gui/kbm_help_dialog.h

@@ -70,6 +70,12 @@ A: The code recognises the line as wrong, and skip it, so the rest of the file w
 
 Q: I want to bind <input> to <output>, but your code doesn't support <input>!
 A: Some keys are intentionally omitted, but if you read the bindings through, and you're sure it is not there and isn't one of the intentionally disabled ones, open an issue on https://github.com/shadps4-emu/shadPS4.
+
+Q: What does default.ini do?
+A: If you're using per-game configs, it's the base from which all new games generate their config file. If you use the unified config, then this is used for every game directly instead.
+
+Q: What does the use Per-game Config checkbox do?
+A: It controls whether the config is loaded from CUSAXXXXX.ini for a game, or from default.ini. This way, if you only want to manage one set of bindings, you can do so, but if you want to use a different setup for every game, that's possible as well.
 )";
     }
     QString syntax() {