What is '$r' in the synopsis?

[szabgab]

It would be nice if you could clarify what is $r in the synopsis and how do we get it?

[powerman]

It's well-known (for Mojolicious developers) name for routes object, used all of time in Mojo docs like:

• https://metacpan.org/pod/Mojolicious#routes
• https://metacpan.org/pod/distribution/Mojolicious/lib/Mojolicious/Guides/Routing.pod#Minimal-route
• https://metacpan.org/pod/distribution/Mojolicious/lib/Mojolicious/Guides/Cookbook.pod#Making-your-application-installable

Personally I don't think this have to be clarified in docs, but I'll accept PR with this change, so feel free to add what you think is missing/unclear in doc. :)