Fix broken link to WebXR Geometry guide (mdn#4385)

files/en-us/web/api/webxr_device_api/startup_and_shutdown/index.html

@@ -276,7 +276,7 @@ <h3 id="Preparing_to_render_the_scene">Preparing to render the scene</h3>
 <p>At this point, the <code>XRSession</code> itself has been fully configured, so we can begin rendering. First, we need a reference space within which coordinates for the world will be stated. We can get the initial reference space for the session by calling the <code>XRSession</code>'s {{domxref("XRSession.requestReferenceSpace", "requestReferenceSpace()")}} method. We specify when calling <code>requestReferenceSpace()</code> the name of the type of reference space we want; in this case, <code>unbounded</code>. You might just as easily specify <code>local</code> or <code>viewer</code>, depending on your needs.</p>
 
 <div class="notecard note">
-<p>To understand how to select the right reference space for your needs, see {{SectionOnPage("en-US/docs/Web/API/WebXR_Device_API/Geometry", "Selecting the reference space type")}}.</p>
+<p>To understand how to select the right reference space for your needs, see {{SectionOnPage("/en-US/docs/Web/API/WebXR_Device_API/Geometry", "Selecting the reference space type")}}.</p>
 </div>
 
 <p>The reference space returned by <code>requestReferenceSpace()</code> places the origin (0, 0, 0) in the center of the space. This is great—if your player's viewpoint starts in the exact center of the world. But most likely, that's not the case at all. If that's so, you call {{domxref("XRReferenceSpace.getOffsetReferenceSpace", "getOffsetReferenceSpace()")}} on the initial reference space to create a <em>new</em> reference space <a href="/en-US/docs/Web/API/WebXR_Device_API/Geometry#establishing_the_reference_space">which offsets the coordinate system</a> so that (0, 0, 0) is located at the position of the viewer, with the orientation likewise shifted to face in the desired direction. The input value into <code>getOffsetReferenceSpace()</code> is an {{domxref("XRRigidTransform")}} encapsulating the player's position and orientation as specified in the default world coordinates.</p>