docs: update howto_contribute: pants-reviews exists
docs: update howto_contribute: pants-reviews exists

Let us not be mired in nostalgia for the time when pants-devel could handle the traffic of our many, many code reviews.

Reviewed at https://rbcommons.com/s/twitter/r/424/

foursquare/pants,pgroudas/pants,lahosken/pants,jtrobec/pants,kwlzn/pants,foursquare/pants,wisechengyi/pants,ity/pants,mateor/pants,manasapte/pants,ericzundel/pants,lahosken/pants,UnrememberMe/pants,wisechengyi/pants,kslundberg/pants,scode/pants,cevaris/pants,wisechengyi/pants,Gabriel439/pants,benjyw/pants,lahosken/pants,megaserg/pants,twitter/pants,jtrobec/pants,baroquebobcat/pants,twitter/pants,qma/pants,scode/pants,sameerparekh/pants,tdyas/pants,tejal29/pants,kwlzn/pants,ericzundel/pants,landism/pants,15Dkatz/pants,benjyw/pants,jtrobec/pants,gmalmquist/pants,foursquare/pants,landism/pants,15Dkatz/pants,dbentley/pants,pombredanne/pants,mateor/pants,pantsbuild/pants,pantsbuild/pants,di0spyr0s/pants,pgroudas/pants,ericzundel/pants,jessrosenfield/pants,dgomez10/xanon,di0spyr0s/pants,foursquare/pants,landism/pants,sid-kap/pants,jessrosenfield/pants,kslundberg/pants,tejal29/pants,UnrememberMe/pants,Gabriel439/pants,Gabriel439/pants,wisechengyi/pants,megaserg/pants,ity/pants,15Dkatz/pants,sid-kap/pants,tdyas/pants,kwlzn/pants,digwanderlust/pants,dturner-tw/pants,sameerparekh/pants,tdyas/pants,sid-kap/pants,gmalmquist/pants,square/pants,dgomez10/xanon,peiyuwang/pants,slyphon/pants,scode/pants,areitz/pants,cevaris/pants,ity/pants,sid-kap/pants,ity/pants,benjyw/pants,pgroudas/pants,jtrobec/pants,mateor/pants,scode/pants,tdyas/pants,pantsbuild/pants,benjyw/pants,qma/pants,pombredanne/pants,cevaris/pants,foursquare/pants,manasapte/pants,foursquare/pants,mateor/pants,TansyArron/pants,baroquebobcat/pants,gmalmquist/pants,tejal29/pants,areitz/pants,scode/pants,areitz/pants,Gabriel439/pants,twitter/pants,tejal29/pants,Gabriel439/pants,di0spyr0s/pants,gmalmquist/pants,landism/pants,baroquebobcat/pants,landism/pants,twitter/pants,kwlzn/pants,peiyuwang/pants,scode/pants,kslundberg/pants,sameerparekh/pants,fkorotkov/pants,pombredanne/pants,jsirois/pants,laurentgo/pants,UnrememberMe/pants,qma/pants,megaserg/pants,dturner-tw/pants,ity/pants,baroquebobcat/pants,dbentley/pants,dbentley/pants,baroquebobcat/pants,laurentgo/pants,ericzundel/pants,UnrememberMe/pants,landism/pants,jtrobec/pants,slyphon/pants,laurentgo/pants,15Dkatz/pants,areitz/pants,15Dkatz/pants,tdyas/pants,dgomez10/xanon,15Dkatz/pants,peiyuwang/pants,jessrosenfield/pants,qma/pants,benjyw/pants,digwanderlust/pants,fkorotkov/pants,baroquebobcat/pants,jtrobec/pants,kwlzn/pants,peiyuwang/pants,lahosken/pants,jessrosenfield/pants,peiyuwang/pants,dturner-tw/pants,manasapte/pants,slyphon/pants,slyphon/pants,sid-kap/pants,mateor/pants,manasapte/pants,dturner-tw/pants,manasapte/pants,kslundberg/pants,dbentley/pants,cevaris/pants,sid-kap/pants,megaserg/pants,sameerparekh/pants,TansyArron/pants,benjyw/pants,gmalmquist/pants,peiyuwang/pants,jsirois/pants,digwanderlust/pants,15Dkatz/pants,dgomez10/xanon,di0spyr0s/pants,fkorotkov/pants,Gabriel439/pants,slyphon/pants,cevaris/pants,sameerparekh/pants,jessrosenfield/pants,tdyas/pants,laurentgo/pants,dgomez10/xanon,cevaris/pants,dturner-tw/pants,lahosken/pants,baroquebobcat/pants,wisechengyi/pants,laurentgo/pants,qma/pants,UnrememberMe/pants,gmalmquist/pants,TansyArron/pants,jessrosenfield/pants,laurentgo/pants,benjyw/pants,tdyas/pants,square/pants,foursquare/pants,areitz/pants,twitter/pants,areitz/pants,lahosken/pants,TansyArron/pants,square/pants,wisechengyi/pants,UnrememberMe/pants,kslundberg/pants,pantsbuild/pants,gmalmquist/pants,dbentley/pants,UnrememberMe/pants,wisechengyi/pants,landism/pants,pombredanne/pants,dbentley/pants,TansyArron/pants,fkorotkov/pants,cevaris/pants,dgomez10/xanon,ericzundel/pants,sameerparekh/pants,baroquebobcat/pants,pantsbuild/pants,TansyArron/pants,lahosken/pants,pgroudas/pants,slyphon/pants,di0spyr0s/pants,fkorotkov/pants,fkorotkov/pants,mateor/pants,ericzundel/pants,15Dkatz/pants,tejal29/pants,digwanderlust/pants,pombredanne/pants,Gabriel439/pants,lahosken/pants,square/pants,TansyArron/pants,ericzundel/pants,UnrememberMe/pants,dturner-tw/pants,kwlzn/pants,twitter/pants,peiyuwang/pants,jessrosenfield/pants,dgomez10/xanon,fkorotkov/pants,digwanderlust/pants,dturner-tw/pants,megaserg/pants,twitter/pants,fkorotkov/pants,slyphon/pants,pgroudas/pants,pgroudas/pants,ity/pants,baroquebobcat/pants,wisechengyi/pants,tdyas/pants,landism/pants,dgomez10/xanon,dgomez10/xanon,pantsbuild/pants,manasapte/pants,scode/pants,sameerparekh/pants,di0spyr0s/pants,pombredanne/pants,pombredanne/pants,megaserg/pants,mateor/pants,kslundberg/pants,dgomez10/xanon,wisechengyi/pants,sid-kap/pants,manasapte/pants,jtrobec/pants,dbentley/pants,dgomez10/xanon,qma/pants,peiyuwang/pants,foursquare/pants,megaserg/pants,di0spyr0s/pants,pantsbuild/pants,UnrememberMe/pants,kwlzn/pants,mateor/pants,areitz/pants,ity/pants,tdyas/pants,kslundberg/pants,twitter/pants,foursquare/pants,qma/pants,digwanderlust/pants,ericzundel/pants,twitter/pants,jsirois/pants