fix jabref format of month

Author: sfo

src/main/java/org/jabref/logic/importer/fileformat/MedlineImporter.java

@@ -607,7 +607,7 @@ private void addPubDate(Map<Field, String> fields, PubDate pubDate) {
             if (pubDate.getMonth() != null) {
                 Optional<Month> month = Month.parse(pubDate.getMonth());
                 if (month.isPresent()) {
-                    fields.put(StandardField.MONTH, month.get().getShortName());
+                    fields.put(StandardField.MONTH, month.get().getJabRefFormat());
                 }
             } else if (pubDate.getSeason() != null) {
                 fields.put(new UnknownField("season"), pubDate.getSeason());

src/main/java/org/jabref/model/entry/Month.java

@@ -175,7 +175,7 @@ public String getShortName() {
      * @return Month in JabRef format
      */
     public String getJabRefFormat() {
-        return String.format("#%s#", shortName);
+        return String.format("%s", shortName);
     }
 
     /**