router: type-safe helpers for multiplex routes

[unknwon]

Component

Core framework

Middleware

n/a

Is your feature request related to a problem? Please describe

Currently multiplex routes are supported via:

f.Routes("/", http.MethodGet, http.MethodPost, <my handlers>)

// or

f.Routes("/", "GET,POST", ...)

But neither of are both elegant and type-safe.

Describe the solution you'd like

Something like

f.RoutePath("/").Methods(http.MethodGet, http.MethodPost).Handlers(...)

Describe alternatives you've considered

Live with it

Additional context

Derived from #113 (comment)

Code of Conduct

• I agree to follow this project's Code of Conduct

[unknwon]

Related in terms of underlying types: #132