How do I stop Visual Studio from automatically adding the end-of-comment characters when I start a new comment in a CSS file

I’m afraid there isn’t an option to change this in Visual Studio, at least not one I can see.
I’ve had the same issue sometimes, and generally use three ways around it:

1. Select the lines to comment out and use the keyboard shortcut: CTRL+K, C
2. Cut the closing */ and paste it at the end of the location
3. Press CTRL+Z to undo the closing */

The first is the best method, but if I’ve already started typing 2 or 3 are enough to get through the break in flow!