import_inter() tests to see if Inter is imported and registered. If
Inter, isn't imported and registered, then import_inter() imports and
registers Inter with
library(extrafont).
Details
Note: Inter must be installed on your computer for import_inter() to
work. Inter is Brooking's main font. To install, visit
Google fonts and click
"Download family". Unzip and open each of the .ttf files and click install.