Remove the trailing new-line character in autocompletions

Solves issue imagej#232 which affected functions pulled from the doc html files.
The behaviour seems to have been inadvertedly introduced in merge imagej#220.

src/main/java/net/imagej/legacy/plugin/MacroAutoCompletionProvider.java

@@ -236,6 +236,10 @@ private BasicCompletion makeListEntry(
 			headline = headline.substring(0, headline.length() - 2);
 		}
 
+		if (headline.endsWith("\n")) {
+			headline = headline.substring(0, headline.length() - 1);
+		}
+
 		return new BasicCompletion(provider, headline, null, description);
 	}