theme specification for captions not used in ggplot2 examples

[mine-cetinkaya-rundel]

In the ggplot2 examples there are some theme specifications for captions, e.g.

plot.caption = element_text(hjust = 0, face= "italic"),
plot.caption.position = "plot"

I believe these are not used since the plots don't have captions. Were they supposed to have captions or should these be removed? I'm happy to send in a PR but I wasn't sure which way to go. 🐧

[allisonhorst]

Haha yeah that does imply that we intended to add captions at some point, thank you Mine! I think we should add captions to all of the images & figures. I really need to refresh the package based on this and a few other PRs, I'll add it to the to-do list w/plans to do some housekeeping in the next couple of weeks.

[koliharesh]

Hello Sir/Madam, I would like to contribute in your project to solve this issue.