overleaf_push.RdPushes any charts that haven't made it to Overleaf yet. You only
need this if you saved charts with grattan_save_overleaf(push =
FALSE), or if a push failed earlier in your session.
overleaf_push()TRUE if charts were pushed, otherwise FALSE,
invisibly.
Saving many charts with push = FALSE and calling
overleaf_push() once at the end is quicker than pushing each chart
as it's saved, because it contacts Overleaf once rather than once per
chart.
if (FALSE) { # \dontrun{
set_overleaf_project("https://www.overleaf.com/project/0123456789abcdef01234567")
grattan_save_overleaf("figure1.pdf", p1, push = FALSE)
grattan_save_overleaf("figure2.pdf", p2, push = FALSE)
overleaf_push()
} # }