A couple of weeks ago, we updated the email composer and the item details editor in plans to use our new formatting editor. This editor was originally optimized solely for sending emails and was a bit simplified. When we released it for editing your plan item details, we were reminded by many customers that they were used to having more options there.
Today we brought back the two main options that were missing, numeric font-sizes and horizontal lines. If you click the first formatting button, instead of having generic options like large and huge, you can now pick from specific point sizes. We also added a button to insert a horizontal line. These buttons are now available anywhere you can add formatting from within Services.