Documentation fix for IT99. Changed kex to tex.
Still needs to be changed at homepage: http://www.nmr-relax.com/analyses/relaxation_dispersion.html#IT99
bug #22019: (https://gna.org/bugs/?22019) The IT99 model is listed with parameter kex instead of tex.
Authored by: tlinnet 2014-05-08
Parent: [r23101]
Child: [r23103]