Simplify `else if`statement

src/mesh/MeshData.hpp

@@ -199,8 +199,7 @@ class MeshData : public IMeshData
     const CellValue<const Rd> cell_iso_barycenter = this->cellIsoBarycenter();
     if constexpr (Dimension == 1) {
       m_cell_centroid = cell_iso_barycenter;
-    } else {
-      if constexpr (Dimension == 2) {
+    } else if constexpr (Dimension == 2) {
       const CellValue<const double> Vj = this->Vj();
       const NodeValue<const Rd>& xr    = m_mesh.xr();
       const auto& cell_to_node_matrix  = m_mesh.connectivity().cellToNodeMatrix();
@@ -279,7 +278,6 @@ class MeshData : public IMeshData
       m_cell_centroid = cell_centroid;
     }
   }
-  }
 
   PUGS_INLINE
   void