Recommend rustfmt --edition=2021

Author: camelid

src/building/suggested.md

@@ -33,7 +33,7 @@ you can write: <!-- date: 2021-09 --><!-- the date comment is for the edition be
     ],
     "rust-analyzer.rustfmt.overrideCommand": [
         "./build/TARGET_TRIPLE/stage0/bin/rustfmt",
-        "--edition=2018"
+        "--edition=2021"
     ],
     "editor.formatOnSave": true,
     "rust-analyzer.cargo.runBuildScripts": false,

src/getting-started.md

@@ -293,7 +293,7 @@ format-on-save turned on. It's a good habit to run `./x.py fmt` before every
 commit, as this reduces conflicts later. The pinned version is built under
 `build/<target>/stage0/bin/rustfmt`, so if you want, you can use it for a
 single file or for format-on-save in your editor, which can be faster than `./x.py fmt`.
-You'll have to pass the <!-- date: 2021-09 --> `--edition=2018` argument
+You'll have to pass the <!-- date: 2021-09 --> `--edition=2021` argument
 yourself when calling `rustfmt` directly.
 
 One last thing: you can use `RUSTC_LOG=XXX` to get debug logging. [Read more