Refactor moveTab for clarity...
Refactor moveTab for clarity...

... as suggested by @mrmr1993 in #1728.

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