Minor: examples/todomvc - Rename Todos::new() as Todos::default().

[martinfrances107]

This is just a minor point seen while copying code snippets from the examples directory

Here is a snippet from this clippy rule new_without_default

struct Foo(Bar);

impl Foo {
fn new() -> Self {
Foo(Bar::new())
}
}
Instead, use:

struct Foo(Bar);

impl Default for Foo {
fn default() -> Self {
Foo(Bar::new())
}
}

both new() and default() are not needed - when just default() will suffice.

[benwis]

LGTM thanks for the contribution!