Make output for contrasts validation more concise

[delfiterradas]

Closes: nf-core/differentialabundance#481

[pinin4fjords]

Thanks for this PR! The changes improve error messaging and reduce verbosity effectively. I have a few suggestions:

R/accessory.R - Minor spacing inconsistency

In the error message formatting, there's an inconsistency in the paste() separators:

• missing_vars uses ", " (comma + space)
• reference_list uses "," (comma only)

Consider making them consistent for better readability:

"Available ", reference_list_name, ": ", paste(unique(reference_list), collapse = ", ")

exec/validate_fom_components.R - Overly aggressive suppression?

The library loading now uses:

suppressMessages(suppressWarnings(library(shinyngs, quietly = TRUE, warn.conflicts = FALSE)))

This seems redundant and potentially too aggressive:

• quietly = TRUE already suppresses messages, making suppressMessages() redundant
• warn.conflicts = FALSE already handles conflicts
• suppressWarnings() will hide ALL warnings, including potentially legitimate ones

Consider using just:

library(shinyngs, quietly = TRUE, warn.conflicts = FALSE)

This should achieve the goal of reducing noise while still allowing genuine warnings to surface if needed.

Overall

The core improvement to checkListIsSubset() is excellent - showing only missing variables instead of all tested values makes the error messages much more actionable. Nice work addressing the verbosity issue!