Make #prop(into, default) a bit more ergonomic.

[gzp79]

At the momement MaybeSignal and similar component properties can be constructed like this:

#prop(into, default = false.into()) disabled: MaybeSignal<bool>
#prop(into, default = "Some value".into()) disabled: MaybeSignal<String>

While this is working when components with many default props are created, the into() calls on the default creates a lot of noise, boilerplate. So I'd suggest to make the .into() call part of the proc-macro:

#prop(into, default = false) disabled: MaybeSignal<bool>
#prop(into, default = "Some value") disabled: MaybeSignal<String>

I think the extra into when it is not required would be compiled to a no-op.
Also this feature could be enabled only when both the input and default tags are present in the annotation.

[gbj]

Any interest in making a PR?