[Feature]: add suggestion to warning files for F_method 2 or 3 to nudge users towards F_method 4

[iantaylor-NOAA]

Describe the solution you would like.

As noted in https://github.com/nmfs-stock-synthesis/doc/issues/154, F_method 4 can replicate F_method 2 and 3 (although @chantelwetzel-noaa noted that further testing could be conducted).

An additional element that might be valuable is a suggestion in the warnings file, similar to https://github.com/nmfs-stock-synthesis/stock-synthesis/blob/e239245af3c27620df8b4b4bcab42b54bb2b2f7a/SS_readcontrol_330.tpl#L226

Describe alternatives you have considered

• educate users through the user manual or a vignette rather than the warnings file (might not get the message through as well)
• automatically convert options 2 and 3 to option 4 (might be too pushy)

Statistical validity, if applicable

No response

Describe if this is needed for a management application

No response

Additional context

No response