tiny whitespace fix

Author: cowtowncoder

yaml/src/main/java/com/fasterxml/jackson/dataformat/yaml/YAMLGenerator.java

@@ -653,7 +653,7 @@ public final void writeEndObject() throws IOException
      */
 
     @Override
-    public void writeString(String text) throws IOException,JsonGenerationException
+    public void writeString(String text) throws IOException, JsonGenerationException
     {
         if (text == null) {
             writeNull();