remove ref to key_traldf_eiv

doc/latex/NEMO/subfiles/apdx_algos.tex

@@ -436,7 +436,7 @@ has been proved (see \autoref{apdx:ALGOS_Gf_operator}).
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 \subsection{Eddy induced velocity and skew flux formulation}
 
-When Gent and McWilliams [1990] diffusion is used (\key{traldf\_eiv} defined),
+When Gent and McWilliams [1990] diffusion is used,
 an additional advection term is added.
 The associated velocity is the so called eddy induced velocity,
 the formulation of which depends on the slopes of iso-neutral surfaces.