MatchExpressionRule - ignore reportAlwaysTrueInLastCondition with enums

[vrana]

This code is fine:

match ($this) {
	self::ONE => 'One',
	self::TWO => 'Two',
	self::THREE => 'Three',
};

Enabling reportAlwaysTrueInLastCondition forces me to write worse code:

match ($this) {
	self::ONE => 'One',
	self::TWO => 'Two',
	default => 'Three',
};

It's worse for two reasons:

1. self::THREE is not explicitly listed making it less obvious what the last arm does.
2. If I add another case to the enum then the first code will correctly report an error but the second won't.