Auto merge of #497 - rbtcollins:patch-1, r=pietroalbini

Remove stale recommendation about Defender

We fixed the performance problem installing docs last year when we overhauled rustup's performance and got Microsoft's Defender team to look into the Defender behaviour vis-a-vis Rustup. It shouldn't be a problem now, and the bug is closed.

Also we now support a minimal profile for automated intallations where no human is present, so adding that seems useful to further speed things up.

docs/agent-machine-setup-windows.md

@@ -105,17 +105,12 @@ which is installed by default on newer versions of Windows or available via
 
 ```powershell
 curl.exe -o rustup-init.exe https://win.rustup.rs/x86_64
-.\rustup-init.exe
+.\rustup-init.exe --profile=minimal
 ```
 
 [rustup-download]: https://github.com/rust-lang/rustup.rs/issues/829
 ["Trusted Sites"]: https://www.itg.ias.edu/content/how-add-trusted-sites-internet-explorer
 
-Disabling "Real-time Protection" in "Settings > Update & Security > Windows
-Defender" may speed up [the installation of `rust-docs`][rust-docs].
-
-[rust-docs]: https://github.com/rust-lang/rustup.rs/issues/1540
-
 ## Build crater
 
 The next step is to download and build `crater` just like on a [Linux