Rollup merge of rust-lang#57278 - mati865:config_clippy, r=alexcrichton

Add Clippy to config.toml.example

Omitted in rust-lang#51122

The order is based on https://github.com/rust-lang/rust/blob/ec194646fef1a467073ad74b8b68f6f202cfce97/src/bootstrap/install.rs#L212

Author: kennytm

config.toml.example

@@ -171,7 +171,7 @@
 
 # Installs chosen set of extended tools if enables. By default builds all.
 # If chosen tool failed to build the installation fails.
-#tools = ["cargo", "rls", "rustfmt", "analysis", "src"]
+#tools = ["cargo", "rls", "clippy", "rustfmt", "analysis", "src"]
 
 # Verbosity level: 0 == not verbose, 1 == verbose, 2 == very verbose
 #verbose = 0