Bump nightly version -> 2025-05-21

Author: flip1995

clippy_dev/src/sync.rs

@@ -4,15 +4,22 @@ use std::fmt::Write;
 
 pub fn update_nightly() {
     let date = Utc::now().format("%Y-%m-%d").to_string();
-    let update = &mut update_text_region_fn(
+    let toolchain_update = &mut update_text_region_fn(
         "# begin autogenerated nightly\n",
         "# end autogenerated nightly",
         |dst| {
             writeln!(dst, "channel = \"nightly-{date}\"").unwrap();
         },
     );
+    let readme_update = &mut update_text_region_fn(
+        "<!-- begin autogenerated nightly -->\n",
+        "<!-- end autogenerated nightly -->",
+        |dst| {
+            writeln!(dst, "```\nnightly-{date}\n```").unwrap();
+        },
+    );
 
     let mut updater = FileUpdater::default();
-    updater.update_file("rust-toolchain.toml", update);
-    updater.update_file("clippy_utils/README.md", update);
+    updater.update_file("rust-toolchain.toml", toolchain_update);
+    updater.update_file("clippy_utils/README.md", readme_update);
 }

clippy_utils/README.md

@@ -8,7 +8,7 @@ This crate is only guaranteed to build with this `nightly` toolchain:
 
 <!-- begin autogenerated nightly -->
 ```
-nightly-2025-05-14
+nightly-2025-05-21
 ```
 <!-- end autogenerated nightly -->
 

rust-toolchain.toml

@@ -1,6 +1,6 @@
 [toolchain]
 # begin autogenerated nightly
-channel = "nightly-2025-05-14"
+channel = "nightly-2025-05-21"
 # end autogenerated nightly
 components = ["cargo", "llvm-tools", "rust-src", "rust-std", "rustc", "rustc-dev", "rustfmt"]
 profile = "minimal"