Make the references to features in the help more consistent. (Sylvain Hitier)
diff --git a/runtime/doc/usr_02.txt b/runtime/doc/usr_02.txt
index e83563a..55e28d7 100644
--- a/runtime/doc/usr_02.txt
+++ b/runtime/doc/usr_02.txt
@@ -529,7 +529,7 @@
 	:help -subject
 <		Command-line option "-subject". >
 	:help +subject
-<		Compile-time feature "+subject'. >
+<		Compile-time feature "+subject". >
 	:help EventName
 <		Autocommand event "EventName". >
 	:help digraphs.txt