Rollup merge of #72761 - poliorcetics:use-keyword-doc, r=Dylan-DPC
Rollup merge of #72761 - poliorcetics:use-keyword-doc, r=Dylan-DPC

Added the documentation for the 'use' keyword

This is a partial fix of #34601.

I heavily inspired myself from the Reference on the `use` keyword.

I checked the links when compiling the documentation, they should be ok.

I also added an example for the wildcard `*` in the case of types, because it's behaviour is not *import everything* like one might think at first.

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