auto merge of #18339 : chastell/rust/guide_pattern_fixes, r=nikomatsakis
auto merge of #18339 : chastell/rust/guide_pattern_fixes, r=nikomatsakis

I think it helps to show that the variables introduced in match blocks are indeed independent from the matched variable `x` (especially when `x` is still reachable inside those blocks and might be useful), so this renames them accordingly. Maybe some linter (or language-level warning?) will eventually warn about shadowing `x` in such cases. ;)

I’m not super happy about the matching-on-range example, as it’s too contrived (`e` and `x` are exactly the same here), but I couldn’t come up with something both simple and non-redundant.

rprichard/rust,victorvde/rust,mvdnes/rust,zaeleus/rust,robertg/rust,zaeleus/rust,aneeshusa/rust,seanrivera/rust,GBGamer/rust,hauleth/rust,emk/rust,pelmers/rust,ejjeong/rust,pshc/rust,aepsil0n/rust,kwantam/rust,quornian/rust,philyoon/rust,kimroen/rust,l0kod/rust,omasanori/rust,kwantam/rust,graydon/rust,barosl/rust,TheNeikos/rust,bombless/rust,dwillmer/rust,jashank/rust,aneeshusa/rust,defuz/rust,zachwick/rust,aepsil0n/rust,untitaker/rust,mahkoh/rust,kimroen/rust,defuz/rust,miniupnp/rust,mdinger/rust,nwin/rust,jashank/rust,robertg/rust,sae-bom/rust,philyoon/rust,zubron/rust,jashank/rust,aidancully/rust,quornian/rust,ktossell/rust,reem/rust,kwantam/rust,dinfuehr/rust,barosl/rust,barosl/rust,vhbit/rust,mahkoh/rust,bombless/rust,barosl/rust,nwin/rust,aneeshusa/rust,richo/rust,vhbit/rust,reem/rust,carols10cents/rust,ebfull/rust,KokaKiwi/rust,reem/rust,dinfuehr/rust,ruud-v-a/rust,richo/rust,andars/rust,aidancully/rust,l0kod/rust,emk/rust,zubron/rust,dwillmer/rust,mihneadb/rust,AerialX/rust,0x73/rust,jroesch/rust,rohitjoshi/rust,nwin/rust,avdi/rust,andars/rust,dwillmer/rust,aepsil0n/rust,cllns/rust,AerialX/rust-rt-minimal,sae-bom/rust,AerialX/rust-rt-minimal,miniupnp/rust,robertg/rust,zachwick/rust,pshc/rust,emk/rust,rohitjoshi/rust,barosl/rust,nwin/rust,graydon/rust,ejjeong/rust,XMPPwocky/rust,aidancully/rust,reem/rust,mvdnes/rust,ruud-v-a/rust,0x73/rust,zaeleus/rust,ruud-v-a/rust,robertg/rust,victorvde/rust,philyoon/rust,robertg/rust,GBGamer/rust,kimroen/rust,krzysz00/rust,nwin/rust,krzysz00/rust,seanrivera/rust,krzysz00/rust,GBGamer/rust,mvdnes/rust,rprichard/rust,aidancully/rust,emk/rust,sae-bom/rust,untitaker/rust,pelmers/rust,ebfull/rust,l0kod/rust,rprichard/rust,AerialX/rust-rt-minimal,dwillmer/rust,cllns/rust,GBGamer/rust,GBGamer/rust,cllns/rust,untitaker/rust,kimroen/rust,emk/rust,bombless/rust,aepsil0n/rust,vhbit/rust,aidancully/rust,ktossell/rust,avdi/rust,krzysz00/rust,l0kod/rust,KokaKiwi/rust,pelmers/rust,quornian/rust,avdi/rust,l0kod/rust,mahkoh/rust,barosl/rust,dinfuehr/rust,carols10cents/rust,aneeshusa/rust,jroesch/rust,jashank/rust,rohitjoshi/rust,ruud-v-a/rust,ktossell/rust,pshc/rust,jashank/rust,krzysz00/rust,defuz/rust,KokaKiwi/rust,mdinger/rust,rprichard/rust,cllns/rust,ejjeong/rust,mihneadb/rust,hauleth/rust,AerialX/rust,gifnksm/rust,mdinger/rust,pshc/rust,miniupnp/rust,nwin/rust,zubron/rust,krzysz00/rust,kimroen/rust,hauleth/rust,AerialX/rust,XMPPwocky/rust,miniupnp/rust,barosl/rust,dwillmer/rust,victorvde/rust,andars/rust,zachwick/rust,jroesch/rust,dinfuehr/rust,jashank/rust,cllns/rust,zubron/rust,vhbit/rust,mihneadb/rust,kwantam/rust,reem/rust,reem/rust,dinfuehr/rust,seanrivera/rust,mvdnes/rust,ejjeong/rust,aidancully/rust,graydon/rust,mihneadb/rust,seanrivera/rust,zachwick/rust,rohitjoshi/rust,richo/rust,aneeshusa/rust,defuz/rust,mahkoh/rust,quornian/rust,jroesch/rust,KokaKiwi/rust,untitaker/rust,quornian/rust,untitaker/rust,seanrivera/rust,aepsil0n/rust,bombless/rust,TheNeikos/rust,philyoon/rust,bombless/rust,graydon/rust,ejjeong/rust,zubron/rust,rprichard/rust,gifnksm/rust,omasanori/rust,vhbit/rust,ruud-v-a/rust,zachwick/rust,vhbit/rust,jroesch/rust,TheNeikos/rust,aneeshusa/rust,hauleth/rust,untitaker/rust,sae-bom/rust,zubron/rust,AerialX/rust-rt-minimal,gifnksm/rust,ruud-v-a/rust,victorvde/rust,omasanori/rust,richo/rust,avdi/rust,TheNeikos/rust,mihneadb/rust,zachwick/rust,avdi/rust,jroesch/rust,zubron/rust,hauleth/rust,jashank/rust,pshc/rust,miniupnp/rust,GBGamer/rust,pshc/rust,victorvde/rust,AerialX/rust,gifnksm/rust,rohitjoshi/rust,mahkoh/rust,sae-bom/rust,dwillmer/rust,omasanori/rust,vhbit/rust,miniupnp/rust,AerialX/rust-rt-minimal,0x73/rust,carols10cents/rust,omasanori/rust,graydon/rust,gifnksm/rust,GBGamer/rust,cllns/rust,mdinger/rust,mahkoh/rust,pshc/rust,victorvde/rust,ebfull/rust,defuz/rust,AerialX/rust,ebfull/rust,0x73/rust,jashank/rust,ktossell/rust,philyoon/rust,XMPPwocky/rust,0x73/rust,XMPPwocky/rust,pelmers/rust,ktossell/rust,bombless/rust-docs-chinese,jroesch/rust,andars/rust,ktossell/rust,AerialX/rust,vhbit/rust,l0kod/rust,0x73/rust,emk/rust,XMPPwocky/rust,TheNeikos/rust,hauleth/rust,carols10cents/rust,jroesch/rust,zaeleus/rust,robertg/rust,ktossell/rust,andars/rust,seanrivera/rust,mvdnes/rust,rohitjoshi/rust,XMPPwocky/rust,KokaKiwi/rust,carols10cents/rust,ejjeong/rust,ebfull/rust,zubron/rust,miniupnp/rust,nwin/rust,carols10cents/rust,quornian/rust,sae-bom/rust,bombless/rust,l0kod/rust,KokaKiwi/rust,mihneadb/rust,AerialX/rust-rt-minimal,richo/rust,defuz/rust,zaeleus/rust,mdinger/rust,quornian/rust,pelmers/rust,pelmers/rust,GBGamer/rust,zaeleus/rust,emk/rust,kwantam/rust,pshc/rust,graydon/rust,richo/rust,mvdnes/rust,rprichard/rust,0x73/rust,dwillmer/rust,dwillmer/rust,dinfuehr/rust,l0kod/rust,kimroen/rust,kimroen/rust,ebfull/rust,andars/rust,philyoon/rust,gifnksm/rust,mdinger/rust,aepsil0n/rust,TheNeikos/rust,kwantam/rust,nwin/rust,miniupnp/rust,omasanori/rust,avdi/rust