typo fix
typo fix

Related with #560
https://github.com/doorkeeper-gem/doorkeeper/pull/560

[ci skip]

mavenlink/doorkeeper,moneytree/doorkeeper,ezilocchi/doorkeeper,Uysim/doorkeeper,GeekOnCoffee/doorkeeper,vovimayhem/doorkeeper,6fusion/doorkeeper,doorkeeper-gem/doorkeeper,telekomatrix/doorkeeper,EasterAndJay/doorkeeper,kolorahl/doorkeeper,daande/doorkeeper,kolorahl/doorkeeper,ngpestelos/doorkeeper,jasl/doorkeeper,calfzhou/doorkeeper,outstand/doorkeeper,lalithr95/doorkeeper,dollarshaveclub/doorkeeper,ministryofjustice/doorkeeper,doorkeeper-gem/doorkeeper,vanboom/doorkeeper,dollarshaveclub/doorkeeper,nbulaj/doorkeeper,stefania11/doorkeeper,ngpestelos/doorkeeper,daande/doorkeeper,mavenlink/doorkeeper,telekomatrix/doorkeeper,ministryofjustice/doorkeeper,ukasiu/doorkeeper,AICIDNN/doorkeeper,ValMilkevich/doorkeeper,pmdeazeta/doorkeeper,vanboom/doorkeeper,identification-io/doorkeeper,vovimayhem/doorkeeper,outstand/doorkeeper,mavenlink/doorkeeper,stormz/doorkeeper,doorkeeper-gem/doorkeeper,jasl/doorkeeper,pmdeazeta/doorkeeper,ValMilkevich/doorkeeper,outstand/doorkeeper,identification-io/doorkeeper,jasl/doorkeeper,dk1234567/doorkeeper,stefania11/doorkeeper,moneytree/doorkeeper,EasterAndJay/doorkeeper,AdStage/doorkeeper,dk1234567/doorkeeper,Uysim/doorkeeper,stormz/doorkeeper,lalithr95/doorkeeper,ezilocchi/doorkeeper,AICIDNN/doorkeeper,6fusion/doorkeeper,AdStage/doorkeeper,ukasiu/doorkeeper,nbulaj/doorkeeper,GeekOnCoffee/doorkeeper,calfzhou/doorkeeper