Expand the inline help text displayed for theme_sub_*() functions.

The introduction of theme_sub_*() functions has made it much easier to structure and organize theme() customizations. However, when coding in RStudio, the inline help text shown for these functions is always the generic message:

"Arguments that are renamed and passed on to theme()."

As a result, users must manually consult the documentation for theme() to understand the meaning of the available arguments.

Since RStudio already displays inline help during code completion, it would be much more useful if the corresponding documentation from theme() were shown directly for each argument. This would reduce the need to switch between code and documentation and could significantly improve coding efficiency when working with ggplot2 themes.

Start by locating the documentation for the theme_sub_*() functions and the corresponding theme() argument descriptions. Update the inline help so each available argument shows the relevant theme() documentation, then verify the result through RStudio code completion or the project's documentation checks.