Model::default vs 0

[MartinKavik]

Chat - #documentation

Tock: just started working through the new docs. Am on App 1: Counter / Init. You just got done on the previous page talking about how you shouldn't implement Default for Model, then the first thing on this page I see is Model::default(). Now I know it's because it's an int alias, so we're getting i32::default(), but as someone who might have missed that, it's jarring. Maybe just have the init() return 0 directly?

MartinKavik: I was fighting with myself whether there should be:
A) Model::default()
B) 0
C) Change Model to something like:
struct Model {
click_count: u32
}
because a type alias as Model is an edge-case.
So perhaps we should change it to 0. Do we want to change it also in README and /examples/counter?
Also it doesn't break the rule that we shouldn't implement Default for Model - it has been already implemented by Rust std..