Fix Philosophy regarding writexl (#384)

vignettes/philosophy.Rmd

@@ -18,7 +18,7 @@ The core advantage of **rio** is that it makes assumptions that the user is prob
 
  5. **rio** imports from from single-file .zip and .tar archives automatically, without the need to explicitly decompress them. Export to compressed directories is also supported.
 
- 6. **rio** wraps a variety of faster, more stream-lined I/O packages than those provided by base R or the **foreign** package. It uses [**data.table**](https://cran.r-project.org/package=data.table) for delimited formats, [**haven**](https://cran.r-project.org/package=haven) for SAS, Stata, and SPSS files, smarter and faster fixed-width file import and export routines, and [**readxl**](https://cran.r-project.org/package=readxl) and [**openxlsx**](https://cran.r-project.org/package=openxlsx) for reading and writing Excel workbooks.
+ 6. **rio** wraps a variety of faster, more stream-lined I/O packages than those provided by base R or the **foreign** package. It uses [**data.table**](https://cran.r-project.org/package=data.table) for delimited formats, [**haven**](https://cran.r-project.org/package=haven) for SAS, Stata, and SPSS files, smarter and faster fixed-width file import and export routines, and [**readxl**](https://cran.r-project.org/package=readxl) and [**writexl**](https://cran.r-project.org/package=writexl) for reading and writing Excel workbooks.
 
  7. **rio** stores metadata from rich file formats (SPSS, Stata, etc.) in variable-level attributes in a consistent form regardless of file type or underlying import function. These attributes are identified as: