std: Stabilize the `process` module
std: Stabilize the `process` module

This commits blanket marks the API of the `std::process` module as `#[stable]`.
The module's API is very similar to the old `std::old_io::process` API and has
generally had quite a bit of time to bake both before and after the new module
landed.

The one modification made to the API is that `Stdio::capture` is now named
`stdio::piped`.

[breaking-change]

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