Remove the confusing "not necessarily limited" part of the 1.3.4 Orientation note and expand (#4349)

Follow-up to #4348

Assuming that the `here content is NOT necessarily restricted to
landscape or portrait orientation` relates just to the virtual reality
example, this expands what was meant (at least, my understanding of it)

Closes #4346

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Co-authored-by: Mike Gower <[email protected]>

Author: patrickhlauke

guidelines/sc/21/orientation.html

@@ -6,6 +6,6 @@ <h4>Orientation</h4>
 
   <p>Content does not restrict its view and operation to a single display orientation, such as portrait or landscape, unless a specific display orientation is <a>essential</a>.</p>
 
-   <p class="note">Examples where a particular display orientation may be essential are a bank check, a piano application, slides for a projector or television, or virtual reality content where content is not necessarily restricted to landscape or portrait display orientation.</p>
+   <p class="note">Examples where a particular display orientation may be essential are a bank check, a piano application, slides for a projector or television, or virtual reality content where parts of the image (for instance, a status bar or heads-up display) always remain at a fixed orientation relative to the headset screens (and the user's eyes) regardless of the physical orientation of the headset.</p>
 
 </section>