`(mx *Mux) Match(...)` has surprising behaviour when using `(mx *Mux) Route(...)`

If I add a subrouter using `Route`, calling `Match` with the same pattern and any method shows a (what I would consider) false positive. For example:

```
r := chi.NewRouter()

r.Route("/path", func(r chi.Router) {
r.Group(func(r chi.Router) {
r.Get("/all", nil)
})
})
```

I would expect:

* `r.Match(chi.NewRouteContext(), http.MethodGet, "/path")` to be false, and
* `r.Match(chi.NewRouteContext(), http.MethodGet, "/path/all")` to be true

however, the first case is true.

For what it's worth, the contents of the inner subrouter don't appear to matter, so:

```
r := chi.NewRouter()

r.Route("/path", func(chi.Router){})
```

shows the same behaviour in the "/path" case.

As noted this is surprising to me; I would expect no match to occur unless a final handler has been configured (`Get(...)`, `Post(...)` etc).

Below is a more elaborate test setup:

```
package routing

import (
"net/http"
"testing"

"github.com/go-chi/chi/v5"
)

func TestWithAll(t *testing.T) {
r := chi.NewRouter()

r.Route("/path", func(r chi.Router) {
r.Group(func(r chi.Router) {
r.Get("/all", nil)
})
})

assert(t, !r.Match(chi.NewRouteContext(), http.MethodGet, "/path"), "GET /path should not be matched")
assert(t, !r.Match(chi.NewRouteContext(), http.MethodPost, "/path"), "POST /path should not be matched")
assert(t, !r.Match(chi.NewRouteContext(), http.MethodPut, "/path"), "PUT /path should not be matched")
assert(t, !r.Match(chi.NewRouteContext(), http.MethodDelete, "/path"), "DELETE /path should not be matched")
assert(t, r.Match(chi.NewRouteContext(), http.MethodGet, "/path/all"), "GET /path/all should be matched")
}

func TestWithoutAll(t *testing.T) {
r := chi.NewRouter()

r.Route("/path", func(chi.Router){})

assert(t, !r.Match(chi.NewRouteContext(), http.MethodGet, "/path"), "GET /path should not be matched")
assert(t, !r.Match(chi.NewRouteContext(), http.MethodPost, "/path"), "POST /path should not be matched")
assert(t, !r.Match(chi.NewRouteContext(), http.MethodPut, "/path"), "PUT /path should not be matched")
assert(t, !r.Match(chi.NewRouteContext(), http.MethodDelete, "/path"), "DELETE /path should not be matched")
}

func assert(t *testing.T, condition bool, message string) {
if !condition {
t.Errorf(message)
}
}
```

Start with the Mux Match and Route entry points and reproduce the two cases in the issue's TestWithAll and TestWithoutAll examples. Trace how a routed subrouter is represented during matching; done means /path is false for the shown methods, /path/all is true for GET, and the empty Route case also returns false.

Written by the indexing model from the issue text.