Bug 294790 [KeyBindings] LegacyActionTools should support SWT.F13 - F20
bundles/org.eclipse.jface/src/org/eclipse/jface/action/LegacyActionTools.java
* @param text
	 *            The text from which the mnemonic should be extracted; may be
	 *            <code>null</code>
	 * @return The text of the mnemonic; will be {@link #MNEMONIC_NONE} if there
	 *         is no mnemonic;
	 */
	public static final char extractMnemonic(final String text) {
		if (text == null) {
			return MNEMONIC_NONE;
		}
		int index = text.indexOf('&');
		if (index == -1) {
			return MNEMONIC_NONE;
		}
		final int textLength = text.length();
		
		if (index == textLength - 1) {
			return MNEMONIC_NONE;
		}
		
		while (text.charAt(index + 1) == '&') {
			index = text.indexOf('&', ++index);
			if (index == textLength - 1) {
				return MNEMONIC_NONE;
			}
		}
		return text.charAt(index + 1);
	}
	/**
	 * Maps a standard keyboard key name to an SWT key code. Key names are