Docs reference non-existing setting font-base-size

**Describe the bug**

https://vanillaframework.io/docs/settings/font-settings references `$font-base-size`, but I can only find
```
$base-font-sizes: (
base: 1rem,
large: $font-size-largescreen,
) !default;
```
in the source.

Open the linked font-settings documentation and compare its `$font-base-size` reference with the source definition for `$base-font-sizes` shown in the issue. Confirm the intended setting name, update the documentation reference, and verify that the page matches the available source setting.

Written by the indexing model from the issue text.