[css-align-3] Delete stray phrase forgotten in 829a074

Author: fantasai

css-align-3/Overview.bs

@@ -1535,7 +1535,6 @@ Block-Axis (or Cross-Axis) Alignment: the 'align-self' property</h3>
 
 	This section describes the effect of 'align-self'
 	on how the margin box of an absolutely-positioned box
-	which is not statically-positioned
 	is positioned with respect to its (absolute-positioning) containing block.
 
 	<table class="data align-details">