Better error message when running roxygenize in the wrong dir

[ColinFay]

Following this conversation on Twitter :

I think the error message we get when trying to roxygenize() in a dir which is not the package root dir could be improved. For now, it's Error: File file does not exist

> getwd()
[1] "/Users/colin/Seafile/documents_colin/R/attempt"
> # Setting a path that is not the pkg root
> setwd("R/")
> getwd()
[1] "/Users/colin/Seafile/documents_colin/R/attempt/R"
> 
> roxygen2::roxygenise()
First time using roxygen2. Upgrading automatically...
Erreur : File file does not exist
> # Setting the wd to the package root
> setwd("..")
> getwd()
[1] "/Users/colin/Seafile/documents_colin/R/attempt"
# No pblm :
> roxygen2::roxygenise()

Maybe something like Are you calling roxygenise() in a directory which is not the package root directory?.

Colin