[Ada] GNATpp: document the --source-line-breaks switch

2019-07-10  Bob Duff  <duff@adacore.com>

gcc/ada/

	* doc/gnat_ugn/gnat_utility_programs.rst: Document gnatpp's
	--source-line-breaks switch.

From-SVN: r273345

gcc/ada/ChangeLog

+2019-07-10  Bob Duff  <duff@adacore.com>
+
+	* doc/gnat_ugn/gnat_utility_programs.rst: Document gnatpp's
+	--source-line-breaks switch.
+
 2019-07-10  Justin Squirek  <squirek@adacore.com>
 
 	* doc/gnat_rm/implementation_defined_attributes.rst: Add mention

gcc/ada/doc/gnat_ugn/gnat_utility_programs.rst

@@ -3248,6 +3248,14 @@ Alternatively, you may run the script using the following command line:
 
    :switch:`--preserve-line-breaks`
      Preserve line breaks in the input, to the extent possible.
+     By default, line breaks are also inserted at appropriate
+     places.
+
+   .. index:: --source-line-breaks (gnatpp)
+
+   :switch:`--source-line-breaks`
+     Keep the line breaks from the source; do not insert or delete any
+     line breaks.
 
    The ``--comments`` switches are compatible with one another, except
    that the ``--comments-unchanged`` switch disables all other comment