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
* <p>
	 * Value is of type <code>String</code>. A RGB color value encoded as a string
	 * using class <code>PreferenceConverter</code>
	 * </p>
	 * 
	 * @see org.eclipse.jface.resource.StringConverter
	 * @see org.eclipse.jface.preference.PreferenceConverter
	 * @since 2.1
	 */
	public final static String EDITOR_TASK_TAG_COLOR= IJavaColorConstants.TASK_TAG;
	/**
	 * A named preference that controls whether task tags are rendered in bold.
	 * <p>
	 * Value is of type <code>Boolean</code>.
	 * </p>
	 * @since 2.1
	 */
	public final static String EDITOR_TASK_TAG_BOLD= IJavaColorConstants.TASK_TAG + EDITOR_BOLD_SUFFIX;
	/**
	 * A named preference that holds the color used to render javadoc keywords.
	 * <p>
	 * Value is of type <code>String</code>. A RGB color value encoded as a string
	 * using class <code>PreferenceConverter</code>
	 * </p>
	 * 
	 * @see org.eclipse.jface.resource.StringConverter
	 * @see org.eclipse.jface.preference.PreferenceConverter
	 */
	public final static String EDITOR_JAVADOC_KEYWORD_COLOR= IJavaColorConstants.JAVADOC_KEYWORD;
	/**