Sets or gets the displayed rating.
Setting the rating property sets how many icons are displayed in the on
state and what value to show textually if the element is set to show a textual
value.
Set the rating value to a number between 1.0 and 5.0 to display a rating.
The textual value, if set to show, will display the rating value to the
nearest tenth and the rating icons will round that value to the nearest half
icon. For example, if you set rating to 4.24, it will be shown textually as
4.2 and 4 stars will be displayed in the on state. However, if you set it to
4.25, it will be shown textually as 4.3 and 4 and a half stars will be displayed
in the on state.
To reset the ratings display element, restoring it to the empty state, set the rating
property to null or undefined.
Getting the rating property returns the current displayed rating.