code action for return type generation

[scarf005]

return type of some function can be automatically inferred. for example:

def add(a: str, b: str):
    return a + b

It would be useful to have a code action that adds inferred return type to function definition.

[bschnurr]

for now there is an inlayhint setting.. where you can double click on the hint to insert the annotation.

[bschnurr]

We were looking to add a code action to insert as well.