Add references for sdcStatus codes more clearly to package functions/manual

[BJ-Cochrane]

Hello, just a suggestion for sdcTable. It'd be great to include the meaning of the codes for sdcStatus in some of the major functions (makeProblem, primarySupression, protectTable) or the the sdcProblem-class. This will let the user more easily understand the codes when using ?help searches.

The codes are listed in the vignette and I can see they're scattered throughout the reference manual but took it took me a bit of digging to find out what these meant.

Thanks a lot for the package!

[bernhard-da]

@BJ-Cochrane thx. I'll look for a more prominent spot to include this so it’s easier for users to find this information.