Expand sentence about create PEs with only one set of angle values

Clarification that the sentence referred to untrusted (synthetic) PEs

index.html

@@ -418,7 +418,7 @@ <h2><code>PointerEvent</code> Interface</h2>
                 <p>The <dfn><code>PointerEventInit</code></dfn> dictionary is used by the <dfn><code>PointerEvent</code></dfn> interface's constructor to provide a mechanism by which to construct untrusted (synthetic) pointer events. It inherits from the {{MouseEventInit}} dictionary defined in [[UI-EVENTS]]. The steps for constructing an event are defined in [[DOM]]. See the <a href="#examples" title="examples">examples</a> for sample code demonstrating how to fire an untrusted pointer event.</p>
 
                 <div class-"note">Pointer Events include two complementary sets of attributes to express the orientation of a transducer relative the X-Z plane: <dfn><code>tiltX</code></dfn> / <dfn><code>tiltY</code></dfn> (introduced in the original Pointer Events specification), and <dfn><code>altitudeAngle</code></dfn> / <dfn><code>azimuthAngle</code></dfn> (adopted from the <a href="https://w3c.github.io/touch-events/">Touch Events - Level 2</a> specification).
-                    Implementations MUST support both sets of attributes. When a Pointer Event is created, and only one set of values is provided, the complementary set of attributes MUST be calculated and initialized.</div>
+                    Implementations MUST support both sets of attributes. When an untrusted (synthetic) Pointer Event is created programmatically using the constructor, and only one set of values is provided, the complementary set of attributes MUST be calculated and initialized.</div>
 
                 <p>A <a>PointerEvent</a> has an associated <dfn>coalesced event list</dfn> (a list of
                 zero or more <code>PointerEvents</code>). If this event is a <code>pointermove</code>