[css-color-5] Link to issue w3c#5277 from hue interpolation section

Author: LeaVerou

css-color-5/Overview.bs

@@ -779,6 +779,8 @@ One way to do this is <code><i>θ</i> = ((<i>θ</i> % 360) + 360) % 360</code>.
 
 Unless otherwise specified, if no specific hue interpolation algorithm is selected by the host syntax, the default is ''shorter''.
 
+Issue(5277): How do these work when interpolating between multiple colors?
+
 Security and Privacy Considerations {#SecPriv}
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