Guard against input elements which don't support selectionStart/End
Guard against input elements which don't support selectionStart/End

These elements throw an error on access, meaning that we can't do an
existence check.

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