[3109] Add article and trailing newline

doc/devel/contribute.dox

@@ -22,7 +22,7 @@ changes and not get disappointed in the process.
 
 @section contributorGuideWritePatch Writing a patch
 
-Before you start working on a patch or new feature, it is a good idea
+Before you start working on a patch or a new feature, it is a good idea
 to discuss it first with BIND10 developers. You can post your
 questions to bind10-dev
 (https://lists.isc.org/mailman/listinfo/bind10-dev) for general BIND10
@@ -149,4 +149,4 @@ and more. Although it is not possible for non ISC employees to run tests
 on that farm, it is possible that your contributed patch will end up there
 sooner or later.
 
-*/
\ No newline at end of file
+*/