[css3-ui] edits for issue 46

Author: tantek

css-ui/Overview.bs

@@ -981,6 +981,11 @@ If the values are unspecified,
 then the intrinsic hotspot defined inside the image resource itself is used.
 If both the values are unspecific and the referenced cursor has no defined hotspot,
 the effect is as if a value of "0 0" were specified.
+If the coordinates of the hotspot, 
+as specified either inside the image resource or 
+by <x> and <y> values,
+fall outside of the cursor image, 
+they must be clamped (independently) to fit.
 </dd>
 </dl>
 

css-ui/Overview.html

@@ -2389,6 +2389,11 @@ <h4 class="heading settled" data-level="7.1.1" id="cursor"><span class="secno">7
 then the intrinsic hotspot defined inside the image resource itself is used.
 If both the values are unspecific and the referenced cursor has no defined hotspot,
 the effect is as if a value of "0 0" were specified.
+If the coordinates of the hotspot, 
+as specified either inside the image resource or 
+by &lt;x> and &lt;y> values,
+fall outside of the cursor image, 
+they must be clamped (independently) to fit.
 </dd>
 </dl>