Allow runners to forbid `time.Duration` casting on expressions of integer type

[ImprintNav]

Casting integers to time.Duration is usually as incorrect as implicitly assigning integer expressions to constants, variables, fields, and parameters of type time.Duration. You can usually replace instances of time.Duration(x) with x * time.Nanoseconds if you really want to convert your type into nanoseconds.

There should be an analyzer flag which, when enabled, also forbids explicit casts to time.Duration.

[navijation]

This is a lot more intricate than I first realized. Basically the right thing would be to permit "proper" conversions like this:

ticker := time.NewTicker(time.Duration(intervalMillis) * time.Millisecond)

But forbid "improper" conversion like this:

ticker := time.NewTicker(time.Duration(intervalMillis))

I have a proof of concept to implement this. It's not free of bugs, but neither is the underlying project, and it catches the most common footguns.