Doc: fixed regularization term in model-fitting section.

doc/src/Model.rst

@@ -13,7 +13,7 @@ SExtractor can fit models to the images of detected objects since version 2.8. T
 .. math::
   :label: loss_func
 
-  \lambda(\boldsymbol{q}) = \sum_i \left(g\left(\frac{p_i - \tilde{m}_i(\boldsymbol{q})}{\sigma_i}\right)\right)^2 + \sum_j \frac{q_j - \mu_j}{}
+  \lambda(\boldsymbol{q}) = \sum_i \left(g\left(\frac{p_i - \tilde{m}_i(\boldsymbol{q})}{\sigma_i}\right)\right)^2 + \sum_j \left(\frac{q_j - \mu_j}{\rho_j}\right)^2
 
 with respect to components of the model parameter vector :math:`\boldsymbol{q}`. :math:`\boldsymbol{q}` comprises parameters describing the shape of the model and the model pixel coordinates :math:`\boldsymbol{x}`.