Remove some boilerplate code when restoring default mappings
Remove some boilerplate code when restoring default mappings

llimllib/vimium,bkudria/vimium,Lw-Cui/vimium,PickRelated/vimium,willsALMANJ/vimium,cyrixhero/vimium,dimatter/vimium,poacher2k/vimium,zhangmin510/vimium,decaffeinate-examples/vimium,poacher2k/vimium,smblott-github/vimium,Lw-Cui/vimium,cyrixhero/vimium,elderbas/vimium,Robinson10240/vimium,csmalin/vimium,PrestanceDesign/vimium,smblott-github/vimium,VPashkov/vimium,Lw-Cui/vimium,douglas-larocca/vimium,crazypenguincode/vimium,csmalin/vimium,dimatter/vimium,willsALMANJ/vimium,philc/vimium,philc/vimium,decaffeinate-examples/vimium,PickRelated/vimium,mrmr1993/vimium,decaffeinate-examples/vimium,mrmr1993/vimium,VPashkov/vimium,gdh1995/vimium,Robinson10240/vimium,wildeyes/vimium,zhangmin510/vimium,csmalin/vimium,gdh1995/vimium,jb55/vimium-plus,Robinson10240/vimium,justalittlenoob/vimium,justalittlenoob/vimium,Aleroniponi/vimium,tuchangwei/vimium,hhsue/vimium,jb55/vimium-plus,hhsue/vimium,PickRelated/vimium,VPashkov/vimium,elderbas/vimium,elegantwww/vimium,wildeyes/vimium,borgified/vimium,cyrixhero/vimium,mrmr1993/vimium,crazypenguincode/vimium,bkudria/vimium,elegantwww/vimium,Aleroniponi/vimium,Aleroniponi/vimium,borgified/vimium,shaung/vimium,smblott-github/vimium-smblott,willsALMANJ/vimium,tuchangwei/vimium,borgified/vimium,smblott-github/vimium,tuchangwei/vimium,gdh1995/vimium,wildeyes/vimium,PrestanceDesign/vimium,douglas-larocca/vimium,justalittlenoob/vimium,hhsue/vimium,zhangmin510/vimium,philc/vimium,poacher2k/vimium,smblott-github/vimium-smblott,elegantwww/vimium,elderbas/vimium,dimatter/vimium,douglas-larocca/vimium,bkudria/vimium,PrestanceDesign/vimium