RFR: JDK-8220257: fix headings in java.instrument

[Gary Adams]

Need one reviewer for this trivial correction .

After pushing the GPL header update, the h3 to h2 tags will be updated.
The copyright will be changed with the headings, so I'll push that 
change first.
   JDK-8220474: Incorrect GPL header in 
src/java.instrument/share/classes/java/lang/instrument/package-info.java

diff --git 
a/src/java.instrument/share/classes/java/lang/instrument/package-info.java 
b/src/java.instrument/share/classes/java/lang/instrument/package-info.java
--- 
a/src/java.instrument/share/classes/java/lang/instrument/package-info.java
+++ 
b/src/java.instrument/share/classes/java/lang/instrument/package-info.java
@@ -1,11 +1,11 @@
  /*
- * Copyright (c) 2003, 2017, Oracle and/or its affiliates. All rights 
reserved.
+ * Copyright (c) 2003, 2019, 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
   * under the terms of the GNU General Public License version 2 only, as
   * published by the Free Software Foundation.  Oracle designates this
- * particular file as subject to the Classpath exception as provided
+ * particular file as subject to the "Classpath" exception as provided
   * by Oracle in the LICENSE file that accompanied this code.
   *
   * This code is distributed in the hope that it will be useful, but 
WITHOUT
@@ -52,7 +52,7 @@
   * <p> Each of these ways to start an agent is described below.
   *
   *
- * <h3>Starting an Agent from the Command-Line Interface</h3>
+ * <h2>Starting an Agent from the Command-Line Interface</h2>
   *
   * <p> Where an implementation provides a means to start agents from the
   * command-line interface, an agent is started by adding the following 
option
@@ -113,7 +113,7 @@
   * threads, is legal from {@code premain}.
   *
   *
- * <h3>Starting an Agent After VM Startup</h3>
+ * <h2>Starting an Agent After VM Startup</h2>
   *
   * <p> An implementation may provide a mechanism to start agents 
sometime after
   * the the VM has started. The details as to how this is initiated are
@@ -164,7 +164,7 @@
   * by the JVM for troubleshooting purposes).
   *
   *
- * <h3>Including an Agent in an Executable JAR file</h3>
+ * <h2>Including an Agent in an Executable JAR file</h2>
   *
   * <p> The JAR File Specification defines manifest attributes for 
standalone
   * applications that are packaged as <em>executable JAR files</em>. If an
@@ -194,8 +194,8 @@
   * an uncaught exception or error, the JVM will abort.
   *
   *
- * <h3> Loading agent classes and the modules/classes available to the 
agent
- * class </h3>
+ * <h2> Loading agent classes and the modules/classes available to the 
agent
+ * class </h2>
   *
   * <p> Classes loaded from the agent JAR file are loaded by the
   * {@linkplain ClassLoader#getSystemClassLoader() system class loader} 
and are
@@ -242,7 +242,7 @@
   * In other words, a custom system class loader must support the 
mechanism to
   * add an agent JAR file to the system class loader search.
   *
- * <h3>Manifest Attributes</h3>
+ * <h2>Manifest Attributes</h2>
   *
   * <p> The following manifest attributes are defined for an agent JAR 
file:
   *
@@ -311,7 +311,7 @@
   * ignored).
   *
   *
- * <h3>Instrumenting code in modules</h3>
+ * <h2>Instrumenting code in modules</h2>
   *
   * <p> As an aid to agents that deploy supporting classes on the 
search path of
   * the bootstrap class loader, or the search path of the class loader 
that loads
@@ -323,4 +323,4 @@
   * @revised 9
   */