combobox: default icon support, smart icon width

src/routes/+page.svelte

@@ -151,6 +151,12 @@
 		/>
 
 		<Combobox
+			icon={{
+				component: Plus,
+				props: {
+					size: '1.2em'
+				}
+			}}
 			label="Lazy combobox"
 			placeholder="Choose..."
 			options={lazyOptions}