Add Play framework-related regex to codegen tool

[yonlugoh]

Expanded the regex which previously accepted only path names with /scala to also accept |play.* or |app (The issue enclosed suggested to only add play but the scastie example provided has /app in the path name instead of play)

closes #950

[ghostdogpr]

LGTM, thanks! @paulpdaniels wanna have a look?

[paulpdaniels]

Yeah I mistyped. /app is the top level route for play apps. So I don't believe we need the "play" variant just the "app" one but it shouldn't hurt