6251738: Want a top-level summary page that itemizes all spec documents referenced from javadocs (OEM spec)

Reviewed-by: hannesw

Author: jonathan-gibbons

make/Docs.gmk

@@ -69,8 +69,6 @@ JAVADOC_TAGS := \
     -tag beaninfo:X \
     -tag revised:X \
     -tag since.unbundled:X \
-    -tag spec:X \
-    -tag specdefault:X \
     -tag Note:X \
     -tag ToDo:X \
     -tag 'apiNote:a:API Note:' \
@@ -86,6 +84,7 @@ JAVADOC_TAGS := \
     -tag since \
     -tag serialData \
     -tag factory \
+    -tag spec \
     -tag see \
     -taglet build.tools.taglet.ExtLink \
     -taglet build.tools.taglet.Incubating \

src/jdk.compiler/share/classes/com/sun/source/doctree/DocTree.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2011, 2021, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2011, 2022, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -218,6 +218,14 @@ enum Kind {
          */
         SNIPPET("snippet"),
 
+        /**
+         * Used for instances of {@link SpecTree}
+         * representing an {@code @spec} tag.
+         *
+         * @since 20
+         */
+        SPEC("spec"),
+
         /**
          * Used for instances of {@link EndElementTree}
          * representing the start of an HTML element.