fix(head): add missing comma between viewport meta properties

[kuibinlin]

Type of change

• Bug fix (non-breaking change which fixes an issue)

Description

The viewport meta tag in _includes/head.html is missing a comma between the user-scalable and initial-scale properties:

<meta
  name="viewport"
  content="width=device-width, user-scalable=no initial-scale=1, shrink-to-fit=no, viewport-fit=cover"
>

Every other property in the list is comma-separated, but user-scalable=no and initial-scale=1 are separated only by a space, making the value inconsistent with the rest of the list.

Fix

Add the missing comma so all properties are consistently comma-separated:

- content="width=device-width, user-scalable=no initial-scale=1, shrink-to-fit=no, viewport-fit=cover"
+ content="width=device-width, user-scalable=no, initial-scale=1, shrink-to-fit=no, viewport-fit=cover"

There is no behavioral change. Browsers already parse both properties correctly because whitespace is accepted as a separator. This change simply improves the syntax for consistency and validity.

Additional context

No existing issue — noticed while validating the generated HTML.

[cotes2020]

Thanks :)