removing empty lines isn't idempotent

[mvdan]

$ cat f.go
package p

func f() {
	var (
		i int
	)
}
$ cat f.go | gofumpt
package p

func f() {

	var i int

}
$ cat f.go | gofumpt | gofumpt
package p

func f() {
	var i int
}

One shouldn't require multiple runs of gofumpt to get the desired outcome. We should fix this edge case.

[briansorahan]

I just ran into this! I'll see if I can make time to whip up a PR.