Fix "unexpected heading" Javadoc errors on Java 13+.
MODIFY
src/main/java/org/apache/commons/io/DirectoryWalker.java
src/main/java/org/apache/commons/io/DirectoryWalker.java
* behaviour.</li>
* </ul>
*
- * <h3 id="example">1. Example Implementation</h3>
+ * <h2 id="example">1. Example Implementation</h2>
*
* There are many possible extensions, for example, to delete all
* files and '.svn' directories, and return a list of deleted files:
* }
* </pre>
*
- * <h3 id="filter">2. Filter Example</h3>
+ * <h2 id="filter">2. Filter Example</h2>
*
* <p>
* Choosing which directories and files to process can be a key aspect
* option for filtering.
* </p>
*
- * <h3 id="cancel">3. Cancellation</h3>
+ * <h2 id="cancel">3. Cancellation</h2>
*
* <p>
* The DirectoryWalker contains some of the logic required for cancel processing.
* scenarios.
* </p>
*
- * <h4 id="external">3.1 External / Multi-threaded</h4>
+ * <h3 id="external">3.1 External / Multi-threaded</h3>
*
* <p>
* This example provides a public <code>cancel()</code> method that can be
* }
* </pre>
*
- * <h4 id="internal">3.2 Internal</h4>
+ * <h3 id="internal">3.2 Internal</h3>
*
* <p>
* This shows an example of how internal cancellation processing could be implemented.

MODIFY
src/main/java/org/apache/commons/io/FileUtils.java
src/main/java/org/apache/commons/io/FileUtils.java
@@ -1309,13 +1309,13 @@ public static void copyDirectory(final File srcDir, final File destDir,
* it is not guaranteed that those operations will succeed.
* If the modification operation fails, no indication is provided.
* </p>
- * <h3>Example: Copy directories only</h3>
+ * <h4>Example: Copy directories only</h4>
* <pre>
* // only copy the directory structure
* FileUtils.copyDirectory(srcDir, destDir, DirectoryFileFilter.DIRECTORY);
* </pre>
*
- * <h3>Example: Copy directories and txt files</h3>
+ * <h4>Example: Copy directories and txt files</h4>
* <pre>
* // Create a filter for ".txt" files
* IOFileFilter txtSuffixFilter = FileFilterUtils.suffixFileFilter(".txt");
@@ -1361,13 +1361,13 @@ public static void copyDirectory(final File srcDir, final File destDir,
* not guaranteed that those operations will succeed.
* If the modification operation fails, no indication is provided.
* </p>
- * <h3>Example: Copy directories only</h3>
+ * <h4>Example: Copy directories only</h4>
* <pre>
* // only copy the directory structure
* FileUtils.copyDirectory(srcDir, destDir, DirectoryFileFilter.DIRECTORY, false);
* </pre>
*
- * <h3>Example: Copy directories and txt files</h3>
+ * <h4>Example: Copy directories and txt files</h4>
* <pre>
* // Create a filter for ".txt" files
* IOFileFilter txtSuffixFilter = FileFilterUtils.suffixFileFilter(".txt");

MODIFY
src/main/java/org/apache/commons/io/comparator/package.html
src/main/java/org/apache/commons/io/comparator/package.html
<p>This package provides various {@link java.util.Comparator} implementations
for {@link java.io.File}s.
</p>
-<h3>Sorting</h3>
+<h2>Sorting</h2>
<p>
All the compartors include <i>convenience</i> utility <code>sort(File...)</code> and
<code>sort(List)</code> methods.
@@ -39,7 +39,7 @@ <h3>Sorting</h3>
File[] files = NameFileComparator.NAME_COMPARATOR.sort(dir.listFiles());
</pre>
-<h3>Composite Comparator</h3>
+<h2>Composite Comparator</h2>
<p>
The <a href="CompositeFileComparator.html">CompositeFileComparator</a> can be used
to compare (and sort lists or arrays of files) by combining a number other comparators.
@@ -57,7 +57,7 @@ <h3>Composite Comparator</h3>
comparator.sort(files);
</pre>
-<h3>Singleton Instances (thread-safe)</h3>
+<h2>Singleton Instances (thread-safe)</h2>
<p>
The {@link java.util.Comparator} implementations have some <i>convenience</i>
singleton(<i>thread-safe</i>) instances ready to use:

MODIFY
src/main/java/org/apache/commons/io/input/BOMInputStream.java
src/main/java/org/apache/commons/io/input/BOMInputStream.java
* </ul>
*
*
- * <h3>Example 1 - Detect and exclude a UTF-8 BOM</h3>
+ * <h2>Example 1 - Detect and exclude a UTF-8 BOM</h2>
*
* <pre>
* BOMInputStream bomIn = new BOMInputStream(in);
* }
* </pre>
*
- * <h3>Example 2 - Detect a UTF-8 BOM (but don't exclude it)</h3>
+ * <h2>Example 2 - Detect a UTF-8 BOM (but don't exclude it)</h2>
*
* <pre>
* boolean include = true;
* }
* </pre>
*
- * <h3>Example 3 - Detect Multiple BOMs</h3>
+ * <h2>Example 3 - Detect Multiple BOMs</h2>
*
* <pre>
* BOMInputStream bomIn = new BOMInputStream(in,

MODIFY
src/main/java/org/apache/commons/io/monitor/FileEntry.java
src/main/java/org/apache/commons/io/monitor/FileEntry.java
* <li>Children - contents of a directory (see {@link File#listFiles(java.io.FileFilter)})</li>
* </ul>
*
- * <h3>Custom Implementations</h3>
+ * <h2>Custom Implementations</h2>
* <p>
* If the state of additional {@link File} attributes is required then create a custom
* {@link FileEntry} with properties for those attributes. Override the

Fix "unexpected heading" Javadoc errors on Java 13+.