theming

[shannonpileggi]

Pass gtsummary theme elements to gtreg tables

[ddsjoberg]

Anytime we use gtsummary function, the theme elements are passed and used.

What we want here is to be able to use a defined gtsummary theme element meant for a column header in place of a spanning header.

We will need to update these lines of code in tbl_ae() (and friends) to use the theme setting

https://github.com/shannonpileggi/gtreg/blob/a0cdd57f75b98564e7d09aea0d8069031a35d625/R/tbl_ae.R#L194

Will need to confirm that anything a user puts here can apply to gtreg tables AND tbl_summary(). If not, we'll need to think of a mechanism where we can define new theme elements outside of gtsummary. This may need to wait until the gtsummary re-factor, since we'll need to access the internal gtsummary environment that saves the themes....or perhaps we can simply use the theming functions from gtsummary as a way to get at the environment.