Fix link to G+Smo adapter documentation

Author: MakisH

perpendicular-flap-stress/README.md

@@ -27,7 +27,7 @@ Fluid participant:
 
 Solid participant:
 
-* G+Smo (perpendicular-flap-vertex-gismo). This solver includes both linear and nonlinear versions of the Newmark time integrator for time-dependent structural problems. The linear version iterates using a constant stiffness matrix. The nonlinear version iterates using an updated Jacobian matrix to account for material or geometric nonlinearity. By default, the solver runs in linear mode. To switch to nonlinear mode, add `--nonlinear` as option in `run.sh`. For more information, have a look at the [G+Smo adapter documentation](https://precice.org/adapter-gismo-overview.html).
+* G+Smo (perpendicular-flap-vertex-gismo). This solver includes both linear and nonlinear versions of the Newmark time integrator for time-dependent structural problems. The linear version iterates using a constant stiffness matrix. The nonlinear version iterates using an updated Jacobian matrix to account for material or geometric nonlinearity. By default, the solver runs in linear mode. To switch to nonlinear mode, add `--nonlinear` as option in `run.sh`. For more information, have a look at the [G+Smo adapter documentation](https://precice.org/adapter-gismo.html).
 
 ## Running the simulation