[css-grid] Fix capitalization and remove some issues.

Author: fantasai

css-grid/Overview.bs

@@ -1034,7 +1034,7 @@ Grid Items</h2>
 	Its contents will however inherit styles (such as font settings) from the grid container.
 
 <h3 id="grid-item-display">
-	Grid item display</h3>
+	Grid Item Display</h3>
 	A <a>grid item</a> establishes a new formatting context for its contents.
 	The type of this formatting context is determined by its 'display' value, as usual.
 	However, grid items are <dfn>grid-level</dfn> boxes, not block-level boxes:
@@ -1057,7 +1057,7 @@ Grid Items</h2>
 	instead of being wrapped into a single anonymous table.
 
 <h3 id="grid-item-sizing">
-	Grid item sizing</h3>
+	Grid Item Sizing</h3>
 
 	A <a>grid item</a> is sized within the containing block defined by its <a>grid area</a>
 	similarly to an equivalent block-level box in an equivalently-sized containing block,
@@ -1069,9 +1069,6 @@ Grid Items</h2>
 	similar to the flexbox behavior on <a>flex items</a> in the <a>main axis</a>.
 	See [[#min-size-auto]].
 
-	ISSUE: Review implications of intrinsic ratio and Grid's 2D nature.
-
-
 <!--
 <h3 id="position-grid">
 Non-children Grid Items</h3>
@@ -1231,8 +1228,6 @@ Implied Minimum Size of Grid Items</h3>
 		this traversal is trivial and therefore not a performance concern.)
 	</div>
 
-	Issue: Review sanity of <a href="https://github.com/w3c/csswg-drafts/issues/283">2D minimum sizing</a>.
-
 <h2 id='grid-definition'>
 Defining the Grid</h2>