Rollup merge of #23082 - killercup:patch-6, r=alexcrichton
Rollup merge of #23082 - killercup:patch-6, r=alexcrichton

 This should fix #22615. Previously, the playpen links grabbed the content of all `.rusttest` containers on the same level to build the URL. Now they just select the one before the `pre` they are shown in.

I have only tested this by changing the file in my local build of the docs (not by running rustdoc itself).

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