[VnV][telemac3d] Update vasque example with better choices for 2 keywords

- use of gradient conjugate + preconditioning 34 = 2*17 to solve PPE, more
efficient than GMRES or CGSTAB (previous choice) for this example

examples/telemac3d/vasque/doc/vasque.tex

@@ -86,6 +86,11 @@ $z = 0.275\left( \cos(\frac{2\pi}{600}t) -1 \right)$ is imposed,
 The non-hydrostatic version of \telemac{3D} is used.
 To solve the advection, the method of characteristics (scheme \#1) is used for
 velocities.
+
+The conjugate gradient (option 1) combined with preconditioning = 34
+= 2 $\times$ 17 is used for solving PPE as more efficient than GMRES (option 7)
+or the former choice CGSTAB (option 6) for this example.
+
 The time step is 0.5~s for a simulated period of 300~s.
 
 \section{Results}

examples/telemac3d/vasque/t3d_vasque.cas

@@ -41,7 +41,8 @@ MASS-LUMPING FOR DEPTH : 1.
 /
 /  SYSTEMES LINEAIRES DE L'OPTION NON-HYDROSTATIQUE
 /
-SOLVER FOR PPE = 6
+SOLVER FOR PPE = 1
+PRECONDITIONING FOR PPE = 34
 /
 PRECONDITIONING FOR DIFFUSION OF VELOCITIES : 34
 /