Adding eprint*! to the list of macros in the format! family

src/liballoc/fmt.rs

@@ -236,6 +236,8 @@
 //! writeln!     // same as write but appends a newline
 //! print!       // the format string is printed to the standard output
 //! println!     // same as print but appends a newline
+//! eprint!      // the format string is printed to the standard error
+//! eprintln!    // same as eprint but appends a newline
 //! format_args! // described below.
 //! ```
 //!
@@ -264,6 +266,11 @@
 //! print!("Hello {}!", "world");
 //! println!("I have a newline {}", "character at the end");
 //! ```
+//! ### `eprint!`
+//!
+//! The [`eprint!`] and [`eprintln!`] macros are identical to
+//! [`print!`] and [`println!`], respectively, except they emit their
+//! output to stderr.
 //!
 //! ### `format_args!`
 //!
@@ -490,7 +497,10 @@
 //! [`writeln!`]: ../../std/macro.writeln.html
 //! [`write_fmt`]: ../../std/io/trait.Write.html#method.write_fmt
 //! [`std::io::Write`]: ../../std/io/trait.Write.html
+//! [`print!`]: ../../std/macro.print.html
 //! [`println!`]: ../../std/macro.println.html
+//! [`eprint!`]: ../../std/macro.eprint.html
+//! [`eprintln!`]: ../../std/macro.eprintln.html
 //! [`write!`]: ../../std/macro.write.html
 //! [`format_args!`]: ../../std/macro.format_args.html
 //! [`fmt::Arguments`]: struct.Arguments.html