[css-grid] Add some issues about placement wording.

Author: tabatkins

css-grid/Overview.bs

@@ -1529,6 +1529,9 @@ Sizing Auto-generated Rows and Columns: the 'grid-auto-rows' and 'grid-auto-colu
 			stacked atop one another.
 			(This happens even if the auto-placed item is greater than 1×1,
 			even if doing so would cause it to overlap explicitly-placed <a>grid items</a>.)
+
+			Issue: Need to clarify what "placed there" means.
+			(See the <a>auto-placement algorithm</a> for details.)
 	</dl>
 
 	Note: A future level of this module is expected to add a value that flows auto-positioned items together into a single “default” cell.
@@ -2323,6 +2326,10 @@ Grid Item Placement Algorithm</h3>
 					</ol>
 			</dl>
 
+			Issue: This needs to be setting up the containing block for the item,
+			not explicitly positioning the item's edges.
+			(Alignment properties can change where in the specified area it actually sits.)
+
 			If 'grid-auto-flow' specifies the ''dense'' keyword,
 			reset the <a>auto-placement cursor</a> to 1/1 each time an item is placed.
 	</ol>