Merge pull request #2224 from pepsiman/patch-1

println! is a macro

src/ch12-06-writing-to-stderr-instead-of-stdout.md

@@ -1,13 +1,13 @@
 ## Writing Error Messages to Standard Error Instead of Standard Output
 
 At the moment, we’re writing all of our output to the terminal using the
-`println!` function. Most terminals provide two kinds of output: *standard
+`println!` macro. Most terminals provide two kinds of output: *standard
 output* (`stdout`) for general information and *standard error* (`stderr`)
 for error messages. This distinction enables users to choose to direct the
 successful output of a program to a file but still print error messages to the
 screen.
 
-The `println!` function is only capable of printing to standard output, so we
+The `println!` macro is only capable of printing to standard output, so we
 have to use something else to print to standard error.
 
 ### Checking Where Errors Are Written