Some clarifications in javadoc

pgpainless-core/src/main/java/org/pgpainless/encryption_signing/ProducerOptions.java

@@ -109,10 +109,13 @@ public final class ProducerOptions {
     }
 
     /**
-     * set the comment for header in ascii armored output.
+     * Set the comment header in ASCII armored output.
      * The default value is null, which means no comment header is added.
      * Multiline comments are possible using '\\n'.
      *
+     * Note: If a default header comment is set using {@link org.pgpainless.util.ArmoredOutputStreamFactory#setComment(String)},
+     * then both comments will be written to the produced ASCII armor.
+     *
      * @param comment comment header text
      * @return builder
      */

pgpainless-core/src/main/java/org/pgpainless/util/ArmoredOutputStreamFactory.java

@@ -61,6 +61,9 @@ public final class ArmoredOutputStreamFactory {
      * Set a comment header value in the ASCII armor header.
      * If the comment contains newlines, it will be split into multiple header entries.
      *
+     * @see org.pgpainless.encryption_signing.ProducerOptions#setComment(String)  for how to set comments for
+     * individual messages.
+     *
      * @param commentString comment
      */
     public static void setComment(String commentString) {