cmd/gofmt: incorrect alignment for func prototype parameters comments

[mkrasuski]

What version of Go are you using (go version)?

1.15.5

Does this issue reproduce with the latest release?

What operating system and processor architecture are you using (go env)?

go env Output

$ go env

What did you do?

just saved file in VSCode - gofmt runs then

What did you expect to see?

func NewHandler(
	fieldName string,   // field to check
	stringValue string, // value to check
	schema Schema,      // source of fields
) *Handler {

What did you see instead?

func NewHandler(
	fieldName string, // field to check
	stringValue string, // value to check
	schema Schema, // source of fields
) *Handler {