Added an option export_raw for showoff() to export unprocessed data

[himcraft]

In Makie, a new data type RichText handles the mathematical representations, e.g., subscript and superscript, for axis labels. This provides an advantage compared with the original returned string by showoff(::automatic, value) that the font of the superscripts can be costomised. As I previously mentioned in a issue of Makie.jl the fonts of basenumbers and powers in axis labels maybe different that can lead to inconsistent visual representation.

My previous solution was to replace all unicode superscipts back to normal digits for further processing. While this approach worked, it was not the most elegant solution. To improve this, I propose adding a new option to showoff() that allows exporting raw strings. This will enable more flexible and precise handling of text formatting, particularly when working with RichText.

Let me know if you’d like further refinements!