Show column sort order.

src/Smartable/Column.tsx

@@ -146,6 +146,8 @@ export function ColumnHeading()
 		<th className={sortState?.type ?? undefined} data-sort-order={sortState?.order ?? undefined}
 		    onMouseDown={handleClick} onContextMenu={disableContextMenu}>
 			{column.title}
+
+			{sortState?.order && <span className={"order"}>{sortState.order}</span>}
 		</th>
 	);
 }

src/styles/_headings.less

@@ -60,5 +60,22 @@ tr.headings
 		{
 			bottom: 0.5em;
 		}
+
+		.order
+		{ // Sort order indicator.
+			position: relative;
+			top: 0;
+			bottom: 0;
+
+			display: block;
+			margin: auto 0;
+			padding: 0.3em 0.3em 0;
+			align-items: center;
+			justify-content: center;
+			color: var(--foreground-lightest);
+			font-size: 0.7em;
+
+			float: right;
+		}
 	}
 }