std/process/command: clarify Command::new behavior for programs with arguments

Author: jieyouxu

library/std/src/process.rs

@@ -606,6 +606,22 @@ impl Command {
  /// but this has some implementation limitations on Windows
  /// (see issue #37519).
  ///
+ /// [`Command::new`] is only intended to accept the path of the program. If you pass a program
+ /// path along with arguments such as `ls -l` for the program `ls` and argument `-l`, it will
+ /// try to search for `ls -l` literally.
+ ///
+ /// ```no_run (example demonstrating incorrect usage)
+ /// use std::process::Command;
+ ///
+ /// // Does not launch `ls`, will try to launch a program named `ls -l` literally.
+ /// Command::new("ls -l")
+ /// .spawn()
+ /// .unwrap();
+ /// ```
+ ///
+ /// The arguments need to be passed separately, such as via [`Command::arg`] or
+ /// [`Command::args`].
+ ///
  /// # Platform-specific behavior
  ///
  /// Note on Windows: For executable files with the .exe extension,