Make a new `R2PptxElement`. Element represent text, a flextable, an image, a ggplot2, etc to add to a slide.
# S4 method for class 'R2PptxLocation'
new_element(key, value)`R2PptxLocation` object created with new_location()
object. Object to put into a PowerPoint slide, eg text or a plot.
An object of class R2PptxElement representing something to put
on a slide.