path_signal() as alternative to query_signal()

[jvdwrf]

Is your feature request related to a problem? Please describe.
I would like to be able to easily create a two-way-binding between path parameters, and what is displayed in my components.

Describe the solution you'd like
An implementation of path_signal(), that allows me to update my components and the url in one go.

Describe alternatives you've considered
Don't know how this can be done currently in an easy manner.