Document sync-mode in porting guide

Author: MakisH

pages/docs/couple-your-code/couple-your-code-porting-v2-3.md

@@ -90,7 +90,7 @@ error: ‘class precice::SolverInterface’ has no member named ‘initializeDat
 
 ## preCICE configuration file
 
-- The XML tag `<solver-interface>` was removed and all underlying functionality was moved to the `<precice-configuration>` tag. Remove the lines including `<solver-interface>` and `</solver-interface>`, and move any attributes (such as `experimental`) from the `solver-interface` to the `precice-configuration` tag.
+- The XML tag `<solver-interface>` was removed and all underlying functionality was moved to the `<precice-configuration>` tag. Remove the lines including `<solver-interface>` and `</solver-interface>`, and move any attributes (such as `experimental`) from the `solver-interface` to the `precice-configuration` tag. Move the `sync-mode` attribute to the new `<profiling>` tag (see below).
 - The `dimensions` configuration is now defined per mesh. Move the `dimensions="2"` or `dimensions="3"` from the `<solver-interface>` tag to each `<mesh>` tag: `<mesh name="MeshOne" dimensions="3">`.
 - Replace mapping constraint `scaled-consistent` with `scaled-consistent-surface`.
 - Replace `<use-mesh provide="true" ... />` with `<provide-mesh ... />`, and `<use-mesh provide="false" ... />` with `<receive-mesh ... />`.