Rollup merge of #57654 - ehuss:fs-links, r=alexcrichton
Rollup merge of #57654 - ehuss:fs-links, r=alexcrichton

Add some links in std::fs.

A few items were referenced, but did not have links.

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