standalone ifs being statements breaks oneof type

[InnocentZero]

new-nu-parser/src/typechecker.rs

Lines 483 to 497 in 22df7ad

	if let Some(else_blk) = else_block {
	let else_type_id =
	if let AstNode::Block(_) = self.compiler.ast_nodes[else_blk.0] {
	self.typecheck_block(else_blk, expected)
	} else {
	self.typecheck_expr(else_blk, expected)
	};
	let mut types = HashSet::new();
	types.insert(then_type_id);
	types.insert(else_type_id);
	self.create_oneof(types)
	} else {
	// If there's no else block, the if expression is a statement
	NONE_TYPE
	}

The comment on the else branch here is wrong since

let x = if $y < $z { 1 }

should resolve the type of $x to oneof<nothing, int>, not nothing. This breaks oneof type semantics that nushell currently uses.