fix for error code preloading HB theme fonts

A note for addition to next update.

I am consistently getting warnings in Chrome browser console that may slow down the site load: The resource “path to my WP/wp-content/themes/HighendWP/assets/css/fonts/source-sans.woff2″ (and source-sans-italic.woff2 and hbicons.woff2) was preloaded using link preload but not used within a few seconds from the window’s load event. Please make sure it has an appropriate ‘as’ value and it is preloaded intentionally.”

So I guess in the header there must be a link rel=’preload’ for the fonts but maybe it still needs an [as=’font’] value.

Thanks!