Auto merge of #13445 - notJoon:modify-dead-links, r=lnicola
Auto merge of #13445 - notJoon:modify-dead-links, r=lnicola

fix) update broken links in guide.md

Hi, I Just fixed some broken links in `guide.md`.

In most cases, it is not connected by an old version (expecially `guide-2019-01`) of the link, so I made some modifications.

Thanks for your time :)

rust-analyzer/rust-analyzer,rust-analyzer/rust-analyzer,rust-analyzer/rust-analyzer,rust-analyzer/rust-analyzer,rust-analyzer/rust-analyzer