mismatch of documentation and implementation regarding how to specify design for DESeq2.

[mschilli87]

The docstring claims design should be a formula when method="DESeq2": https://github.com/HelenaLC/muscat/blob/49a3b323133921fdcd9772441df0aa2ee09ab1e1/R/pbDS.R#L13

However, pbDS calls .check_args_pbDS before considering method: https://github.com/HelenaLC/muscat/blob/49a3b323133921fdcd9772441df0aa2ee09ab1e1/R/pbDS.R#L95

That function immediately fails if design is anything but a matrix: https://github.com/HelenaLC/muscat/blob/49a3b323133921fdcd9772441df0aa2ee09ab1e1/R/validity-checks.R#L153-L154

So how would I run DESeq2 for ~ batch + group_id instead of the default ~ group_id?