Improve documentation comments in the code

Author: renatho

packages/block-library/src/cover/save.js

@@ -143,6 +143,12 @@ export default function save( { attributes } ) {
 				/>
 			) }
 
+			{ /* The `wp-block-cover__background` needs to be immediately before
+			the `wp-block-cover__inner-container`, so the exclusion CSS selector
+			`.wp-block-cover__background + .wp-block-cover__inner-container`
+			works properly. If it needs to be changed in the future, the
+			selector for the backward compatibility for v14 deprecation also
+			needs change. */ }
 			<span
 				aria-hidden="true"
 				className={ clsx(

packages/block-library/src/cover/style.scss

@@ -94,7 +94,7 @@
 	}
 
 	.wp-block-cover__inner-container {
-		position: relative; // Needed after the v14 deprecation..
+		position: relative; // Needed for the inner container to be positioned above other elements with absolute positioning.
 		width: 100%;
 		color: inherit;
 		// Reset the fixed LTR direction at the root of the block in RTL languages.
@@ -289,13 +289,14 @@ section.wp-block-cover-image > h2,
 }
 
 // Backward compatibility for v14 deprecation. Only applied to the frontend.
+// Regarding the `.wp-block-cover__background + .wp-block-cover__inner-container`
+// selector: When the `.wp-block-cover__inner-container` comes right after the
+// `.wp-block-cover__background` , it means that it's using the new HTML
+// structure or that it's using the color background or gradient (even in
+// the deprecated version). In the color background or gradient option we don't
+// need the z-index because the elements are in the expected order.
 body:not(.editor-styles-wrapper) .wp-block-cover:not(
 .wp-block-cover:has(
-	/* When the `.wp-block-cover__inner-container` comes right after the
-	`.wp-block-cover__background` , it means that it's using the new HTML
-	structure or that it's using the color background or gradient (even in
-	the deprecated version). In the last option we also don't need the z-index
-	because the elements are in the expected order. */
 	.wp-block-cover__background + .wp-block-cover__inner-container
 )
 ) {