> invalid_df("must be integer", "col", "\nFix this.")
[1] "Column `col` must be integer.\nFix this."

> invalid_df("must be numeric", c("col1", "col2"))
[1] "Columns `col1` and `col2` must be numeric."

> use_repair(TRUE)
[1] "\nUse .name_repair to specify repair."

> use_repair(FALSE)
