Clarify that disabled does not prevent all modifications

Closes #7168.

Author: domenic

source

@@ -54907,6 +54907,12 @@ interface <dfn interface>HTMLOptionElement</dfn> : <span>HTMLElement</span> {
 
   </div>
 
+  <p class="note">Being <span data-x="concept-option-disabled">disabled</span> does not prevent all
+  modifications to the <code>option</code> element. For example, its <span
+  data-x="concept-option-selectedness">selectedness</span> could be modified programmatically from
+  JavaScript. Or, it could be indirectly modified by user action, e.g., if other non-disabled
+  <code>option</code> elements in the <code>select</code> element were modified.</p>
+
   <p>The <dfn element-attr for="option"><code data-x="attr-option-label">label</code></dfn>
   attribute provides a label for element. The <dfn data-x="concept-option-label">label</dfn> of an
   <code>option</code> element is the value of the <code data-x="attr-option-label">label</code>
@@ -57071,9 +57077,20 @@ form.method === input; // => true</code></pre>
 
   <div w-nodev>
 
-  <p>A form control that is <span data-x="concept-fe-disabled">disabled</span> must prevent any <code
-  data-x="event-click">click</code> events that are <span data-x="queue a task">queued</span> on the
-  <span>user interaction task source</span> from being dispatched on the element.</p>
+  <p>A form control that is <span data-x="concept-fe-disabled">disabled</span> must prevent any
+  <code data-x="event-click">click</code> events that are <span data-x="queue a task">queued</span>
+  on the <span>user interaction task source</span> from being dispatched on the element.</p>
+
+  </div>
+
+  <p class="note">Being <span data-x="concept-fe-disabled">disabled</span> does not prevent all
+  modifications to the form control. For example, the control's <span
+  data-x="concept-fe-value">value</span> or <span data-x="concept-fe-checked">checkedness</span>
+  could be modified programmatically from JavaScript. Or, they could be indirectly modified by user
+  action, e.g., if other non-disabled elements in the control's <span>radio button group</span> were
+  modified.</p>
+
+  <div w-nodev>
 
   <p><strong>Constraint validation</strong>: If an element is <span
   data-x="concept-fe-disabled">disabled</span>, it is <span>barred from constraint