I think what you are talking about is the little "Auto Correct" Lightning Bolt (shown in my first picture).
This Lightning Bolt?
Auto Correct Options
To remove it, if you mouse over it, you should be able to click on the little black arrow that will appear and then you get the list of options. The bottom one is "Control AutoFormat Options..." If you click on that, you will get a window like I have in the 2nd picture.
Now, what option you need to disable, I'm not sure as I have never modified these. However, maybe someone else can take it from here.
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