Auto merge of #25571 - hirschenberger:master, r=nrc
Auto merge of #25571 - hirschenberger:master, r=nrc

It is hard to find the actual unstable feature which caused the error when using a list of stable and unstable features as the span marks the whole line

```
src/k8055.rs:22:1: 22:64 error: unstable feature
src/k8055.rs:22 #![feature(slice_patterns, rustc_private, core, convert, libc)]
                ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
```

This PR spawns an error for each unstable feature in the list:

```
est.rs:1:12: 1:26 error: unstable feature [-D unstable-features]
test.rs:1 #![feature(slice_patterns, rustc_private, core, convert, libc)]
                     ^~~~~~~~~~~~~~
test.rs:1:28: 1:41 error: unstable feature [-D unstable-features]
test.rs:1 #![feature(slice_patterns, rustc_private, core, convert, libc)]
                                     ^~~~~~~~~~~~~
test.rs:1:43: 1:47 error: unstable feature [-D unstable-features]
test.rs:1 #![feature(slice_patterns, rustc_private, core, convert, libc)]
                                                    ^~~~
test.rs:1:49: 1:56 error: unstable feature [-D unstable-features]
test.rs:1 #![feature(slice_patterns, rustc_private, core, convert, libc)]
                                                          ^~~~~~~
test.rs:1:58: 1:62 error: unstable feature [-D unstable-features]
test.rs:1 #![feature(slice_patterns, rustc_private, core, convert, libc)]
                                                                   ^~~~
```

omasanori/rust,sae-bom/rust,XMPPwocky/rust,andars/rust,aepsil0n/rust,KokaKiwi/rust,KokaKiwi/rust,sae-bom/rust,jroesch/rust,cllns/rust,cllns/rust,zubron/rust,GBGamer/rust,mvdnes/rust,seanrivera/rust,jroesch/rust,jashank/rust,jashank/rust,mvdnes/rust,mvdnes/rust,KokaKiwi/rust,zachwick/rust,pshc/rust,jroesch/rust,KokaKiwi/rust,philyoon/rust,aidancully/rust,seanrivera/rust,robertg/rust,pshc/rust,aepsil0n/rust,gifnksm/rust,omasanori/rust,graydon/rust,cllns/rust,jashank/rust,cllns/rust,reem/rust,philyoon/rust,sae-bom/rust,aneeshusa/rust,XMPPwocky/rust,ejjeong/rust,GBGamer/rust,XMPPwocky/rust,philyoon/rust,omasanori/rust,TheNeikos/rust,zubron/rust,nwin/rust,KokaKiwi/rust,kwantam/rust,pshc/rust,seanrivera/rust,pelmers/rust,mihneadb/rust,l0kod/rust,jashank/rust,vhbit/rust,andars/rust,jroesch/rust,vhbit/rust,seanrivera/rust,kwantam/rust,nwin/rust,zubron/rust,robertg/rust,XMPPwocky/rust,l0kod/rust,GBGamer/rust,mvdnes/rust,dwillmer/rust,dwillmer/rust,nwin/rust,cllns/rust,pelmers/rust,robertg/rust,aepsil0n/rust,sae-bom/rust,gifnksm/rust,krzysz00/rust,aepsil0n/rust,zubron/rust,ejjeong/rust,mihneadb/rust,vhbit/rust,jroesch/rust,aepsil0n/rust,aneeshusa/rust,zachwick/rust,zachwick/rust,philyoon/rust,kwantam/rust,GBGamer/rust,jroesch/rust,zachwick/rust,zachwick/rust,mihneadb/rust,carols10cents/rust,robertg/rust,sae-bom/rust,mvdnes/rust,carols10cents/rust,nwin/rust,nwin/rust,pelmers/rust,kwantam/rust,l0kod/rust,aneeshusa/rust,dwillmer/rust,zubron/rust,pshc/rust,graydon/rust,omasanori/rust,dwillmer/rust,gifnksm/rust,andars/rust,kwantam/rust,mihneadb/rust,aidancully/rust,robertg/rust,XMPPwocky/rust,sae-bom/rust,andars/rust,jashank/rust,zubron/rust,vhbit/rust,aneeshusa/rust,nwin/rust,gifnksm/rust,philyoon/rust,vhbit/rust,krzysz00/rust,ejjeong/rust,ejjeong/rust,kwantam/rust,carols10cents/rust,aneeshusa/rust,graydon/rust,nwin/rust,mihneadb/rust,ejjeong/rust,pshc/rust,seanrivera/rust,krzysz00/rust,reem/rust,krzysz00/rust,TheNeikos/rust,jroesch/rust,l0kod/rust,XMPPwocky/rust,reem/rust,aidancully/rust,zubron/rust,TheNeikos/rust,graydon/rust,robertg/rust,carols10cents/rust,aidancully/rust,reem/rust,jashank/rust,graydon/rust,KokaKiwi/rust,pshc/rust,aneeshusa/rust,vhbit/rust,dwillmer/rust,cllns/rust,mvdnes/rust,gifnksm/rust,jroesch/rust,nwin/rust,gifnksm/rust,andars/rust,l0kod/rust,aidancully/rust,ejjeong/rust,pshc/rust,carols10cents/rust,l0kod/rust,aidancully/rust,l0kod/rust,pshc/rust,TheNeikos/rust,pelmers/rust,jashank/rust,dwillmer/rust,mihneadb/rust,aepsil0n/rust,seanrivera/rust,GBGamer/rust,vhbit/rust,reem/rust,l0kod/rust,vhbit/rust,omasanori/rust,TheNeikos/rust,andars/rust,jashank/rust,philyoon/rust,krzysz00/rust,GBGamer/rust,carols10cents/rust,krzysz00/rust,GBGamer/rust,reem/rust,zubron/rust,graydon/rust,TheNeikos/rust,pelmers/rust,dwillmer/rust,zachwick/rust,omasanori/rust,pelmers/rust,GBGamer/rust,dwillmer/rust