Improved documentation to user function relax_disp.r2eff_err_estimate, and removed the possibility to use the chi2 Jacobian, as this is rubbish.
But the back-end still have this possibility, should one desire to try this.
task #7822(https://gna.org/task/index.php?7822): Implement user function to estimate R2eff and associated errors for exponential curve fitting.
Authored by: tlinnet 2014-08-29
Parent: [r25466]
Child: [r25468]
