[#6649] Changing a note to a caution - this *is* a gotcha

Author: weaverryan

Diff for: forms.rst

@@ -573,7 +573,7 @@ the correct values of a number of field options.
     guessed from the validation constraints (if ``Length`` or ``Range`` is used) or
     from the Doctrine metadata (via the field's length).
 
-.. note::
+.. caution::
 
   These field options are *only* guessed if you're using Symfony to guess
   the field type (i.e. omit or pass ``null`` as the second argument to ``add()``).