docs(equations): added contributions documentation

src/include/serif/equations/angular_momentum.hpp

@@ -39,6 +39,8 @@ namespace serif::equations
      *
      * Use this equation in conjunction with a RigidRotation object to constrain the angular momentum of a system to some fixed value. Note that this constraint
      * is weakly applied and therefore should be checked for convergence in the final solution.
+     *
+     * @contribution Residuals to the global angular momentum
      */
     class AngularMomentumConstraint final : public Contribution<discretization::forms::Operand<discretization::blocks::rotation::angular_velocity>>
     {

src/include/serif/equations/arithmetic.hpp

@@ -50,6 +50,8 @@ namespace serif::equations {
          * @param equation The equation to scale.
          * @param coefficient The coefficient to scale the equation by. Must be finite.
          *
+         * @contribution Residuals to all rows which are shared by the summed equations
+         *
          * @throws std::invalid_argument If the coefficient is not finite.
          */
         explicit EquationScale(
@@ -97,6 +99,8 @@ namespace serif::equations {
      *
      * @requires The FirstT and RestTs equations must share the same test type, otherwise the summation is not well-defined.
      *
+     * @contribution Residuals to all rows which are shared by the summed equations
+     *
      * @note Only equations sharing a residual row can or should be summed together.
      *
      * @tparam FirstT The first equation type to sum.
@@ -146,6 +150,8 @@ namespace serif::equations {
      *
      * @requires The left and right equations must share the same test type, otherwise the subtraction is not well-defined.
      *
+     * @contribution Residuals to all rows which are shared by the summed equations
+     *
      * @note Only equations sharing a residual row can or should be subtracted from one another.
      *
      * @tparam LeftT The left equation type to subtract from.