Update in the tcplfit2 vignette mc4_mthds_id table

[sedavid01]

Issue: There is a incorrect/mis-aligned definition regarding the bmad.aeid.lowconc.nwells compared with the definition in the mc4_mthds table for tcpl.

Needs:

• Verify the definition for bmad.aeid.lowconc.nwells in tcpl mc4_mthds, and that there are no methods named bmad.aeid.nwells.
• Ensure with the context of the vignette that the table needs updated.
• Fix the description in the tcplfit2 vignette table describing mc4 bmad methods.