Rollup merge of #74192 - xkr47:patch-1, r=Mark-Simulacrum
Rollup merge of #74192 - xkr47:patch-1, r=Mark-Simulacrum

Improve documentation on process::Child.std* fields

As a relative beginner, it took a while for me to figure out I could just steal the references to avoid partially moving the child and thus retain ability to call functions on it (and store it in structs etc).

graydon/rust,aidancully/rust,graydon/rust,aidancully/rust,graydon/rust,aidancully/rust,aidancully/rust,graydon/rust,graydon/rust,aidancully/rust,aidancully/rust,graydon/rust