Add prominent note, and additional note, about being pointer-device-specific

Author: patrickhlauke

mediaqueries/Overview.bs

@@ -1637,6 +1637,12 @@ Interaction Media Features</h2>
 	in response to changes in the user environment 
 	or in the way the user is interacting with the UA.
 
+	Note: The 'pointer', 'hover', 'any-pointer' and 'any-hover' features only relate to the characteristics,
+	or the complete absence, of pointing devices,
+	and can not be used to detect the presence of non-pointing device input mechanisms such as keyboards.
+	Authors should take into account the potential presence of non-pointing device inputs,
+	regardless of which values are matched when querying these features. 
+
 <h3 id="pointer">
 Pointing Device Quality: the 'pointer' feature</h3>
 
@@ -1816,6 +1822,9 @@ All Available Interaction Capabilities: the 'any-pointer' and 'any-hover' featur
 	As such, it should be understood as a query to test if any hover-capable pointing devices are present,
 	rather than whether or not any of the pointing devices is hover-incapable.
 	The latter scenario can currently not be determined using 'any-hover' or any other interaction media feature.
+	Additionally, it does not take into account any non-pointing device inputs,
+	such as d-pads or keyboard-only controls,
+	which by their very nature are also not hover-capable.
 	</div>
 
 	<div class="example">