`ss3rep` parameter documentation

[efletcherPIFSC]

The parameter ss3rep is used and documented in the following functions:

• SSCompsTA1.8: Stock Synthesis output as read by r4SS function SS_output
• SSdeltaMVLN: from r4ss::SS_output
• SSdeltaMVLN_old: from r4ss::SSgetoutput()$replist1
• SSdiagsMCMC: from r4ss::SS_output
• SSdiagsMCMC_ancient: from r4ss::SS_output
• SSsettingsBratioF: from r4ss::SSgetoutput()
• SSrmse: output from SS_output()
• SSplotRunsTest: Stock Synthesis output as read by r4SS function SS_output

With the exception used in SSdeltaMVLN_old, the documentation can be consolidated to state ss3rep is an Stock Synthesis output object generated by r4ss::SS_output.

[efletcherPIFSC]

Value for SSdeltaMVLN_old come from the replist1 parameter of [r4ss::SSgetoutput()]

The rest of the functions can state it came from [r4ss::SS_output()]

[MOshima-PIFSC]

I think its ok to change this to match the others. The SSgetoutput function is used to get multiple outputs at once but the function only takes one output. This was probably an artifact of how the function was used in a script at one point. To be consistent I would use [r4ss::SS_output()].