Bug 40772 [plan item] Smart tab on empty lines
When having the caret on an empty line, pressing tab cleans up the line and sets the caret it the right indentation column.
org.eclipse.jdt.ui/ui/org/eclipse/jdt/ui/PreferenceConstants.java
* <code>javaEditorTextHovers</code>.
	 *
	 * @since 2.1
	 */
	public static String ID_SOURCE_HOVER= "org.eclipse.jdt.ui.JavaSourceHover"; 
	/**
	 * The id of the javadoc hover contributed for extension point
	 * <code>javaEditorTextHovers</code>.
	 *
	 * @since 2.1
	 */
	public static String ID_JAVADOC_HOVER= "org.eclipse.jdt.ui.JavadocHover"; 
	/**
	 * The id of the problem hover contributed for extension point
	 * <code>javaEditorTextHovers</code>.
	 *
	 * @since 2.1
	 */
	public static String ID_PROBLEM_HOVER= "org.eclipse.jdt.ui.ProblemHover"; 
	/**
	 * A named preference that controls whether bracket matching highlighting is turned on or off.
	 * <p>
	 * Value is of type <code>Boolean</code>.
	 * </p>
	 */
	public final static String EDITOR_MATCHING_BRACKETS= "matchingBrackets"; 
	/**
	 * A named preference that holds the color used to highlight matching brackets.
	 * <p>
	 * Value is of type <code>String</code>. A RGB color value encoded as a string