Add a note to section 10.1 of tutor

Add a note to the tutor in section 10.1 to
prevent new users from thinking Helix is buggy
or that the user is doing something wrong.

NOTE: If typing ) or ( appears to do nothing, try using a theme
 that uses different colors for primary selection and cursor.
 These themes work well here:
 - dark_plus
 - emacs

runtime/tutor

@@ -1007,7 +1007,10 @@ lines.
  --> How much would would a wouldchuck chuck
  --> if a wouldchuck could chuck would?
 
-
+ NOTE: If typing ) or ( appears to do nothing, try using a 
+ different color theme. These themes work well here:
+ - dark_plus
+ - emacs
 
 
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