proposal: Hope to provide arrow functions 'syntax

[Lizhooh]

Hope to provide arrow functions 'syntax.

How do you like it?

add := func(a int, b int) int {
    return a + b
}

// arrow functions
add := (a int, b int) int => a + b

[davecheney]

Thank you for raising this issue. This appears to be a duplicate of, or have a great deal of overlap with #21498. I am closing this issue as the other has more detail and more discussion.