Support publisher webpage in Vorbis comments

tag.h

@@ -126,6 +126,7 @@ enum class KnownField : unsigned int {
     ProductionCopyright, /** production copyright */
     License, /** license */
     TermsOfUse, /** terms of use */
+    PublisherWebpage, /** the publisher's official webpage */
 };
 
 /*!
@@ -136,7 +137,7 @@ constexpr KnownField firstKnownField = KnownField::Title;
 /*!
  * \brief The last valid entry in the TagParser::KnownField enum.
  */
-constexpr KnownField lastKnownField = KnownField::TermsOfUse;
+constexpr KnownField lastKnownField = KnownField::PublisherWebpage;
 
 /*!
  * \brief The number of valid entries in the TagParser::KnownField enum.

vorbis/vorbiscomment.cpp

@@ -109,6 +109,8 @@ VorbisComment::IdentifierType VorbisComment::internallyGetFieldId(KnownField fie
         return std::string(bpm());
     case KnownField::Publisher:
         return std::string(publisher());
+    case KnownField::PublisherWebpage:
+        return std::string(publisherWebpage());
     default:
         return std::string();
     }
@@ -149,6 +151,7 @@ KnownField VorbisComment::internallyGetKnownField(const IdentifierType &id) cons
          { rating(), KnownField::Rating },
          { bpm(), KnownField::Bpm },
          { publisher(), KnownField::Publisher },
+         { publisherWebpage(), KnownField::PublisherWebpage },
     });
     // clang-format on
     const auto knownField(fieldMap.find(id));

vorbis/vorbiscommentids.h

@@ -189,6 +189,10 @@ constexpr TAG_PARSER_EXPORT std::string_view bpm()
 {
     return "BPM";
 }
+constexpr TAG_PARSER_EXPORT std::string_view publisherWebpage()
+{
+    return "WWWPUBLISHER";
+}
 
 } // namespace VorbisCommentIds