Remove warnings when creating package due to docs

[sshanks-kx]

When doing mvn clean package created various warnings when creating javadocs e.g.

[INFO] --- maven-javadoc-plugin:3.2.0:jar (attach-javadocs) @ javakdb ---
[INFO] No previous run data found, generating javadoc.
[WARNING] Javadoc Warnings
[WARNING] Loading source files for package kx...
[WARNING] Loading source files for package kx.examples...
[WARNING] Constructing Javadoc information...
[WARNING] Building index for all the packages and classes...
[WARNING] Standard Doclet version 18.0.2+0
[WARNING] Building tree for all the packages and classes...
[WARNING] Generating /Users/simon/Development/javakdb2/javakdb/target/apidocs/kx/c.html...
[WARNING] Generating /Users/simon/Development/javakdb2/javakdb/target/apidocs/kx/c.Dict.html...
[WARNING] Generating /Users/simon/Development/javakdb2/javakdb/target/apidocs/kx/c.Flip.html...
[WARNING] Generating /Users/simon/Development/javakdb2/javakdb/target/apidocs/kx/c.IAuthenticate.html...
[WARNING] Generating /Users/simon/Development/javakdb2/javakdb/target/apidocs/kx/c.KException.html...
[WARNING] Generating /Users/simon/Development/javakdb2/javakdb/target/apidocs/kx/c.Minute.html...
[WARNING] Generating /Users/simon/Development/javakdb2/javakdb/target/apidocs/kx/c.Month.html...
[WARNING] Generating /Users/simon/Development/javakdb2/javakdb/target/apidocs/kx/c.MsgHandler.html...
[WARNING] Generating /Users/simon/Development/javakdb2/javakdb/target/apidocs/kx/c.Second.html...
[WARNING] Generating /Users/simon/Development/javakdb2/javakdb/target/apidocs/kx/c.Timespan.html...
[WARNING] Generating /Users/simon/Development/javakdb2/javakdb/target/apidocs/kx/examples/Feed.html...
[WARNING] /Users/simon/Development/javakdb2/javakdb/src/main/java/kx/examples/Feed.java:12: warning: use of default constructor, which does not provide a comment
[WARNING] public class Feed{
[WARNING] ^
[WARNING] Generating /Users/simon/Development/javakdb2/javakdb/target/apidocs/kx/examples/GridViewer.html...
[WARNING] /Users/simon/Development/javakdb2/javakdb/src/main/java/kx/examples/GridViewer.java:20: warning: no comment
[WARNING] public static class KxTableModel extends AbstractTableModel {
[WARNING] ^
[WARNING] /Users/simon/Development/javakdb2/javakdb/src/main/java/kx/examples/GridViewer.java:19: warning: use of default constructor, which does not provide a comment
[WARNING] public class GridViewer {
[WARNING] ^

etc