Tests are needed for several functions

[Huh]

Functions that have no tests

• morph_gps
• cllr_remove_header
• style_scale_color
• style_theme
• style_scale_fill

I would appreciate it if @foresthayes could work on morph_gps and @teejclark worked on the plotting stuff. I will take care of cllr_remove_header.

[Huh]

@teejclark if you can write a few tests and check the boxes we will be good, thanks.

Recall that you can type covr::report() in the console and get a report of what is and is not covered for each file.