rollup merge of #23484: alexcrichton/marker-trait-stable
rollup merge of #23484: alexcrichton/marker-trait-stable

This trait has proven quite useful when defining marker traits to avoid the
semi-confusing `PhantomFn` trait and it looks like it will continue to be a
useful tool for defining these traits.

zubron/rust,mihneadb/rust,philyoon/rust,nwin/rust,krzysz00/rust,zaeleus/rust,pelmers/rust,aidancully/rust,zachwick/rust,miniupnp/rust,aidancully/rust,krzysz00/rust,rohitjoshi/rust,mihneadb/rust,mdinger/rust,vhbit/rust,aepsil0n/rust,ruud-v-a/rust,carols10cents/rust,robertg/rust,l0kod/rust,jashank/rust,jashank/rust,carols10cents/rust,ebfull/rust,zaeleus/rust,reem/rust,l0kod/rust,aneeshusa/rust,carols10cents/rust,krzysz00/rust,ejjeong/rust,graydon/rust,aneeshusa/rust,graydon/rust,nwin/rust,aidancully/rust,seanrivera/rust,dwillmer/rust,seanrivera/rust,zubron/rust,kwantam/rust,ruud-v-a/rust,graydon/rust,GBGamer/rust,dwillmer/rust,pshc/rust,rohitjoshi/rust,robertg/rust,mvdnes/rust,robertg/rust,jashank/rust,philyoon/rust,l0kod/rust,robertg/rust,jashank/rust,rohitjoshi/rust,avdi/rust,mihneadb/rust,mvdnes/rust,ruud-v-a/rust,ebfull/rust,omasanori/rust,ruud-v-a/rust,l0kod/rust,rohitjoshi/rust,mdinger/rust,TheNeikos/rust,pshc/rust,l0kod/rust,nwin/rust,omasanori/rust,jroesch/rust,jroesch/rust,ebfull/rust,dwillmer/rust,kwantam/rust,ruud-v-a/rust,sae-bom/rust,mihneadb/rust,rohitjoshi/rust,zaeleus/rust,ejjeong/rust,zubron/rust,philyoon/rust,omasanori/rust,dwillmer/rust,zachwick/rust,zubron/rust,philyoon/rust,KokaKiwi/rust,zubron/rust,reem/rust,nwin/rust,aepsil0n/rust,pshc/rust,miniupnp/rust,dwillmer/rust,avdi/rust,nwin/rust,gifnksm/rust,XMPPwocky/rust,pelmers/rust,victorvde/rust,TheNeikos/rust,kwantam/rust,cllns/rust,krzysz00/rust,gifnksm/rust,philyoon/rust,jroesch/rust,miniupnp/rust,GBGamer/rust,omasanori/rust,XMPPwocky/rust,krzysz00/rust,ebfull/rust,ebfull/rust,zubron/rust,dwillmer/rust,pshc/rust,reem/rust,reem/rust,victorvde/rust,zubron/rust,aidancully/rust,aneeshusa/rust,graydon/rust,gifnksm/rust,mdinger/rust,avdi/rust,KokaKiwi/rust,andars/rust,philyoon/rust,vhbit/rust,vhbit/rust,andars/rust,jroesch/rust,graydon/rust,sae-bom/rust,zaeleus/rust,mvdnes/rust,carols10cents/rust,carols10cents/rust,aepsil0n/rust,mdinger/rust,sae-bom/rust,jroesch/rust,aepsil0n/rust,seanrivera/rust,GBGamer/rust,cllns/rust,omasanori/rust,miniupnp/rust,krzysz00/rust,victorvde/rust,miniupnp/rust,XMPPwocky/rust,GBGamer/rust,GBGamer/rust,victorvde/rust,kwantam/rust,pelmers/rust,kwantam/rust,XMPPwocky/rust,ejjeong/rust,sae-bom/rust,KokaKiwi/rust,reem/rust,aneeshusa/rust,mvdnes/rust,TheNeikos/rust,nwin/rust,mdinger/rust,TheNeikos/rust,vhbit/rust,l0kod/rust,l0kod/rust,miniupnp/rust,victorvde/rust,mvdnes/rust,pelmers/rust,cllns/rust,miniupnp/rust,cllns/rust,zubron/rust,KokaKiwi/rust,aepsil0n/rust,reem/rust,robertg/rust,zachwick/rust,avdi/rust,pshc/rust,pelmers/rust,ruud-v-a/rust,gifnksm/rust,robertg/rust,zachwick/rust,sae-bom/rust,jroesch/rust,aneeshusa/rust,vhbit/rust,pshc/rust,pshc/rust,aidancully/rust,nwin/rust,gifnksm/rust,mihneadb/rust,zachwick/rust,KokaKiwi/rust,seanrivera/rust,pelmers/rust,ejjeong/rust,jroesch/rust,aidancully/rust,KokaKiwi/rust,zaeleus/rust,TheNeikos/rust,jashank/rust,TheNeikos/rust,jroesch/rust,GBGamer/rust,kwantam/rust,vhbit/rust,cllns/rust,aneeshusa/rust,nwin/rust,jashank/rust,cllns/rust,graydon/rust,mihneadb/rust,pshc/rust,seanrivera/rust,dwillmer/rust,avdi/rust,victorvde/rust,ejjeong/rust,zaeleus/rust,XMPPwocky/rust,ebfull/rust,XMPPwocky/rust,l0kod/rust,GBGamer/rust,andars/rust,dwillmer/rust,avdi/rust,miniupnp/rust,jashank/rust,zachwick/rust,sae-bom/rust,ejjeong/rust,GBGamer/rust,seanrivera/rust,jashank/rust,mvdnes/rust,carols10cents/rust,andars/rust,rohitjoshi/rust,andars/rust,andars/rust,gifnksm/rust,vhbit/rust,aepsil0n/rust,vhbit/rust,omasanori/rust,mdinger/rust