Explicit covariate compartment

[stemangiola]

@mikelove and I received the feedback that we should be explicit about which column comes from the colData and so the covariate becomes explicit, communicating what the experimental design is.

I was thinking possibly adding a header line above the column names.

# A SummarizedExperiment-tibble abstraction: 800 × 14
# Features=100 | Samples=8 | Assays=counts
                            | -- COVARIATES ----------|
.sample | .feature | .count | treatment | batch | age | ... | chromosome | gene_feature | ... | 
 <chr>           <chr>       <int> <fct>      <fct>  <fct> <fct> <fct>      

Or any more elegant visuals

[mikelove]

I like being explicit like this. And I agree from that conversation that communication of our rich data structure is how we can lead the way.