Rollup merge of #33675 - apasel422:issue-33662, r=pnkfelix
Rollup merge of #33675 - apasel422:issue-33662, r=pnkfelix

Add missing code fence to `diagnostics.rs`

Closes #33662

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