Undocumented stateful route behaviour

[Madoshakalaka]

This is about:

• A typo
• Innaccurate/misleading documentation (e.g. technically incorrect advice)
• Undocumented code
• Outdated documentation
• Other

Problem

Undocumented behavior: the router will try to redirect to the not found route when the deserialization fails:

#[derive(Clone, Routable, PartialEq)]
enum Route {
    #[at("/news/:id")]
    News{id: u8},
    #[not_found]
    #[at("/404")]
    NotFound,
}

News accepts an u8, but when the id goes over 255, the router redirects to the not found route.

The behavior is vaguely mentioned here

yew/packages/yew-router/src/switch.rs

Line 59 in 47fad81

/// When a route can't be matched, it looks for the route with `not_found` attribute.

If this is intended behavior, It needs to be documented.
The comment might also need to be more specific:

-  When a route can't be matched, it looks for the route with `not_found` attribute.
+ When a route can't be matched, including when the path is matched but the deserialization fails, it looks for the route with `not_found` attribute. 

[voidpumpkin]

This is intended

[voidpumpkin]

@Madoshakalaka PR to add docs is much appreciated or just add to your currently open PR.

[Madoshakalaka]

@voidpumpkin Will add to the existing PR then