8219992: Correct the documentation of PrintWriter to refer System.lineSeparator

[Brian Burkhalter]

https://bugs.openjdk.java.net/browse/JDK-8219992 <https://bugs.openjdk.java.net/browse/JDK-8219992>

Proposed change included below (excluding copyright year update); CSR to follow.

Thanks,

Brian

--- a/src/java.base/share/classes/java/io/PrintWriter.java
+++ b/src/java.base/share/classes/java/io/PrintWriter.java
@@ -704,9 +704,8 @@
 
     /**
      * Terminates the current line by writing the line separator string.  The
-     * line separator string is defined by the system property
-     * {@code line.separator}, and is not necessarily a single newline
-     * character ({@code '\n'}).
+     * line separator string is defined by the {@link System#lineSeparator()}
+     * method, and is not necessarily a single newline character ({@code '\n'}).
      */
     public void println() {