Update std::fs::remove_dir_all documentation

Author: emilyalbini

library/std/src/fs.rs

@@ -2042,13 +2042,17 @@ pub fn remove_dir<P: AsRef<Path>>(path: P) -> io::Result<()> {
 ///
 /// # Platform-specific behavior
 ///
-/// This function currently corresponds to `opendir`, `lstat`, `rm` and `rmdir` functions on Unix
-/// and the `FindFirstFile`, `GetFileAttributesEx`, `DeleteFile`, and `RemoveDirectory` functions
-/// on Windows.
-/// Note that, this [may change in the future][changes].
+/// This function currently corresponds to `openat`, `fdopendir`, `unlinkat` and `lstat` functions
+/// on Unix (except for macOS before version 10.10 and REDOX) and the `CreateFileW`,
+/// `GetFileInformationByHandleEx`, `SetFileInformationByHandle`, and `NtOpenFile` functions on
+/// Windows. Note that, this [may change in the future][changes].
 ///
 /// [changes]: io#platform-specific-behavior
 ///
+/// On macOS before version 10.10 and REDOX this function is not protected against time-of-check to
+/// time-of-use (TOCTOU) race conditions, and should not be used in security-sensitive code on
+/// those platforms. All other platforms are protected.
+///
 /// # Errors
 ///
 /// See [`fs::remove_file`] and [`fs::remove_dir`].