docs: remove unnecessary quotes from tutorial exercise (#551)

Author: DrumsnChocolate

apps/svelte.dev/content/tutorial/01-svelte/04-logic/04-each-blocks/+assets/app-b/src/lib/App.svelte

@@ -9,7 +9,7 @@
 	{#each colors as color, i}
 		<button
 			style="background: {color}"
-			aria-label="{color}"
+			aria-label={color}
 			aria-current={selected === color}
 			onclick={() => selected = color}
 		>{i + 1}</button>

apps/svelte.dev/content/tutorial/01-svelte/04-logic/04-each-blocks/index.md

@@ -30,7 +30,7 @@ Now we need to use the `color` variable in place of `"red"`:
 	{#each colors as color}
 		<button
 			style="background: +++{color}+++"
-			aria-label="+++{color}+++"
+			aria-label=+++{color}+++
 			aria-current={selected === +++color+++}
 			on:click={() => selected = +++color+++}
 		></button>