allow == false in SimplifyBooleanExpression

In haxe, `== true` is always a mistake, but I prefer `== false` over `!` just because it's so easy to miss a single character.

Would like a way to prevent `== true` but not `== false`.
perhaps:
```json
"type": "SimplifyBooleanExpression"
"props": {
	"allowFalse": true
}
```