Update python/doc/usecases/use_case_stiffened_panel.rst

Co-authored-by: Michael Baudin <31351465+mbaudin47@users.noreply.github.com>

python/doc/usecases/use_case_stiffened_panel.rst

@@ -144,7 +144,7 @@ where:
 - :math:`\bar{A}=A+pt_s+\frac{1}{2}(f_1-f_2)t_c` is the area of the section of
   the full panel (main surface and stiffener) bounded by :math:`p`;
 
-- :math:`h_0=\frac{1}{2\bar{A}}\left[A(h_c+t_c+t_s)+\frac{1}{2}t_c(f_1-f_2)(t_c+t_s)\right]`
+- :math:`h_0=\frac{1}{2\bar{A}} \left(A(h_c+t_c+t_s)+\frac{1}{2}t_c(f_1-f_2)(t_c+t_s)\right)`
   is the distance between the mean surface of the panel main surface and the
   global geometric center of the pa,nel;