[Ada] Document default new-line behavior for GNATpp

2019-07-03  Bob Duff  <duff@adacore.com>

gcc/ada/

	* doc/gnat_ugn/gnat_utility_programs.rst: Document default
	new-line behavior.

From-SVN: r272977

gcc/ada/ChangeLog

+2019-07-03  Bob Duff  <duff@adacore.com>
+
+	* doc/gnat_ugn/gnat_utility_programs.rst: Document default
+	new-line behavior.
+
 2019-07-03  Hristian Kirtchev  <kirtchev@adacore.com>
 
 	* ali.adb: Add with and use clauses for GNAT,

gcc/ada/doc/gnat_ugn/gnat_utility_programs.rst

@@ -3458,6 +3458,8 @@ Alternatively, you may run the script using the following command line:
      * *unix* - UNIX style, lines end with LF character*
      * *lf* -  the same as *unix*
 
+     The default is to use the same end-of-line convention as the input.
+
    .. index:: --wide-character-encoding (gnatpp)
 
    :switch:`--wide-character-encoding={e}`