Coding Standards: Use single quotes for a string in Tests_Comment.

This resolves a WPCS error:
{{{
Error: String "1" does not require double quotes; use single quotes instead.
}}}

Includes updating a few related comments for clarity.

Follow-up to [56221].

See #57855.

git-svn-id: https://develop.svn.wordpress.org/trunk@56222 602fd350-edb4-49c9-b593-d223f7449a82

tests/phpunit/tests/comment.php

@@ -60,7 +60,10 @@ public function test_wp_update_comment() {
 		$this->assertSame( 1, $result );
 
 		$comment = get_comment( $comments[0] );
-		// The factory returns ints, but get_comment returns strings
+		/*
+		 * ::create_post_comments() returns comment IDs as integers,
+		 * but WP_Comment::$comment_parent is a string.
+		 */
 		$this->assertSame( (string) $comments[1], $comment->comment_parent );
 
 		$result = wp_update_comment(
@@ -79,7 +82,7 @@ public function test_wp_update_comment() {
 		);
 
 		$comment = get_comment( $comments[0] );
-		// The factory returns ints, but get_comment returns strings
+		// WP_Post::$ID is an integer, but WP_Comment::$comment_post_ID is a string.
 		$this->assertSame( (string) $post2->ID, $comment->comment_post_ID );
 	}
 
@@ -223,7 +226,7 @@ public function test_wp_update_comment_updates_user_id() {
 		);
 
 		$comment = get_comment( $comment_id );
-		$this->assertSame( "1", $comment->user_id );
+		$this->assertSame( '1', $comment->user_id );
 	}
 
 	/**