[docs] Change 'Echos' to 'Echoes' (#964)

docs/guides/commands/samples/module.cs

@@ -3,7 +3,7 @@ public class Info : ModuleBase<SocketCommandContext>
 {
 	// ~say hello -> hello
 	[Command("say")]
-	[Summary("Echos a message.")]
+	[Summary("Echoes a message.")]
 	public async Task SayAsync([Remainder] [Summary("The text to echo")] string echo)
 	{
 		// ReplyAsync is a method on ModuleBase
@@ -38,4 +38,4 @@ public class Sample : ModuleBase<SocketCommandContext>
 		var userInfo = user ?? Context.Client.CurrentUser;
 		await ReplyAsync($"{userInfo.Username}#{userInfo.Discriminator}");
 	}
-}
+}