Add ability to set a prefix name for routes which have hyphen

With current Rails when you have in your routes

```ruby
get '/contact_us' => 'pages#contact'
get '/about_us'   => 'pages#about_us'
```

you'll get this inspection: 

```shell
           Prefix Verb  URI Pattern                  Controller#Action
       contact_us GET   /contact_us(.:format)        pages#contact
         about_us GET   /about_us(.:format)          pages#about_us
```

---

But when your routes are with hyphen (dash), like so:

```ruby
get '/contact-us' => 'pages#contact'
get '/about-us'   => 'pages#about_us'
```

you'll get this: 

```shell
           Prefix Verb  URI Pattern                  Controller#Action
                  GET   /contact-us(.:format)        pages#contact
                  GET   /about-us(.:format)          pages#about_us
```

Which does lead that theres no helper methods for these routes i.e. `about_us_path`, `contact_us_path`.