[fix] handle promise rejections for {#await} in SSR

src/compiler/compile/render_ssr/handlers/AwaitBlock.ts

@@ -13,7 +13,10 @@ export default function(node: AwaitBlock, renderer: Renderer, options: RenderOpt
 
 	renderer.add_expression(x`
 		function(__value) {
-			if (@is_promise(__value)) return ${pending};
+			if (@is_promise(__value)) {
+				__value.then(() => {}, () => {});
+				return ${pending};
+			}
 			return (function(${node.then_node ? node.then_node : ''}) { return ${then}; }(__value));
 		}(${node.expression.node})
 	`);