Manual style pre processing

[romainfrancois]

For example

iris %>%
  span(group_by, class = "bg_yellow" )( Species ) %>%
  summarise_all( mean )

would apply the css class bg_yellow to group_by and make span disappear of the call tree

[romainfrancois]

perhaps using e.g. ...span... so that it does not clash with htmltools::span

maybe treat all the function calls that look like [.]{3}.*[.]{3} like styling preprocessing commands