HTML Validator Errors

When I look at
https://kopatheme.com/demo/nictitate/
with
https://validator.w3.org/

I see a lot of errors, especially this one:

“Character reference was not terminated by a semicolon.”

<i data-icon=”&#xe014″></i> and so on

where it should be

<i data-icon=””></i>

So I changed line 23 and 25 in custom_walker.php to

$icon = ‘<i data-icon=”‘ . $kopa_icons[$icon] . ‘;”></i>’;

and

$icon = ‘<i data-icon=”‘ . $kopa_icons[‘home’] . ‘;”></i>’;

but this didn’t change anything!?

What to do? Thank you!