better document how to create unexpanded and unsexed comps

[iantaylor-NOAA]

Is your feature request related to a problem? Please describe.
The help page for getComps() https://pfmc-assessments.github.io/pacfintools/reference/getComps.html discusses the use of weightid which is the result of the expansion calculations in get_pacfin_expansions(). However, if users want to create unxpanded comps, it's would be good to provide more info on how to do that. Is there a different column that could be passed to weightid or would users just set Final_Sample_Size_L <- 1 before running getComps()?

Similarly, for processing unsexed composition data (that is, compositions for all fish for use in a single-sex assessment model, as opposed to just unsexed fish separate from the sexed compositiosn), I believe that it would work to add a line like bds_cleaned$SEX <- "U" after running cleanPacFIN() but is there a better way to do this?

Describe the solution you'd like
Additional documentation on creating unexpanded and/or unsexed comps for getComps() and possibly the vignette.
@chantelwetzel-noaa, I'm happy to make the changes but want to check with you on what the recommended methods are before doing so.

Describe alternatives you've considered
Leave it to the user to figure this stuff out.

[chantelwetzel-noaa]

I think if someone wants to created unexpanded comps (ages or lengths) that should be done using the nwfscSurvey::get_raw_comps(). If you agree, then we could add that information to the vignette.

[brianlangseth-NOAA]

@iantaylor-NOAA I am set to do both of these things for quillback this week (unsexed expanded and unsexed unexpanded) - and yes I realized I said that a while ago. Regardless, Im happy to provide my thoughts for the vignette as well.

[iantaylor-NOAA]

@brianlangseth-NOAA, if whatever method you apply works well, please do either paste code into this issue or create a pull request for the vignette.