remove caution block

Author: cristoforocervino

reference/forms/types/options/form_attr.rst.inc

@@ -17,10 +17,4 @@ You can also set this to ``true`` on a root form to automatically set the "form"
 
     When root the form has no ID, ``form_attr`` is required to be a string identifier to be used as the form ID.
 
-.. caution::
-
-    HTML "form" attribute was introduced to let you explicitly bind a control with a form even if it is
-    not nested inside it. Don't forget to check for `browser compatibility`_.
-
 .. _`"form" attribute`: https://html.spec.whatwg.org/multipage/form-control-infrastructure.html#attr-fae-form
-.. _`browser compatibility`: https://caniuse.com/form-attribute