Do not use `...` (dynamic dots) to to collect a single details argument

[eitsupi]

Ref: https://design.tidyverse.org/dots-data.html
Related to #1477

For examples:

• pl$col(...) -> pl$col(names)
• cs$by_name(...) -> cs$by_name(names)
• cs$by_dtype(...) -> cs$by_dtype(dtypes)

[etiennebacher]

Apart from pl$col(), are there other functions concerned by this?

Would this be a breaking change or just an internal change that requires an update to the documentation and error message? In other words, would pl$col("a", "b") still work? 1.0.0 already had a bunch of breaking changes, I'd really avoid changing this core behavior again.

[eitsupi]

Apart from pl$col(), are there other functions concerned by this?

As far as I can think of, cs$by_name() is also applicable. (I was wondering about the different argument types for cs$by_name and cs$by_index when I updated to 1.1.0, but I kept the dots for cs$by_name.)

Would this be a breaking change or just an internal change that requires an update to the documentation and error message? In other words, would pl$col("a", "b") still work? 1.0.0 already had a bunch of breaking changes, I'd really avoid changing this core behavior again.

No, if this change were applied, pl$col("a", "b") would be in error.

So this change needs to be done gradually with deprecations (as outlined in the Tidy design principles).