Try to address Max's markdown comment

modules/fsi/doc/content/source/kernels/ConvectedMesh.md

@@ -6,6 +6,7 @@
 the term:
 
 \begin{equation}
+\label{convection}
 -\rho \left(\frac{\partial\vec{d_m}}{\partial t} \cdot \nabla\right) \vec{u}
 \end{equation}
 

modules/fsi/doc/content/source/kernels/ConvectedMeshPSPG.md

@@ -7,13 +7,22 @@ equation corresponding to the [ConvectedMesh.md] object. It implements the
 weak form
 
 \begin{equation}
-\int \nabla \psi \dot \left(\tau \dot{\vec{d}}\right) dV
+\label{pspg}
+\int \nabla \psi \cdot \left(\tau\frac{\partial\vec{d_m}}{\partial t}\cdot\nabla\vec{u}\right) dV
 \end{equation}
 
 where $\nabla \psi$ is the gradient of the pressure test function, $\tau$ is a
 stabilization parameter computed automatically by the `navier_stokes` base class
-`INSBase`, and $\dot{\vec{d}}$ is the time derivative of the displacement
-vector.
+`INSBase`, $\vec{d_m}$ is the fluid mesh displacements, and
+$\vec{u}$ is the fluid velocity. Note that when comparing [pspg] with
+[!eqref](ConvectedMesh.md#convection) that the minus sign and density $\rho$ have
+disappeared. This is because the form of PSPG stabilization is
+
+\begin{equation}
+\int \nabla \psi \cdot \left(-\frac{\tau}{\rho}\vec{R}\right)
+\end{equation}
+
+where $\vec{R}$ denotes the strong form of the momentum residuals.
 
 !syntax parameters /Kernels/ConvectedMeshPSPG