assist: convert if-let/match to `Option::map`

[pickx]

there should be an assist to convert

match my_optional {
    Some(val) => { do_something(val) }
    None => None,
};

and

if let Some(val) = my_optional {
    do_something(val)
} else {
    None
};

to

my_optional.map(|val| do_something(val));

this manual re-implementation is very common. I'm not saying either is better, just that the ability to do this would be nice.