Fix docstrings escape syntax

src/solvers/dasp3.py

@@ -44,8 +44,8 @@ class DASP3ODE(Explicit_ODE):
     
     .. math::
       
-      \\frac{\mathrm{d}y}{\mathrm{d}t} &=  f(t,y,z) \;\;\;  \\text{(N equations)} \\\\
-      \\varepsilon\\frac{\mathrm{d}z}{\mathrm{d}t} &= G(t,y,z)\;\;\;  \\text{(M equations)}       
+      \\frac{\\mathrm{d}y}{\\mathrm{d}t} &=  f(t,y,z) \\;\\;\\;  \\text{(N equations)} \\\\
+      \\varepsilon\\frac{\\mathrm{d}z}{\\mathrm{d}t} &= G(t,y,z)\\;\\;\\;  \\text{(M equations)}
     
     If is assumed that the first system is non-stiff and that
     the stiffness of the second system is due to the parameter

src/solvers/odepack.py

@@ -48,7 +48,7 @@ class LSODAR(Explicit_ODE):
         
         .. math::
     
-            \dot{y} = f(t,y), \quad y(t_0) = y_0.
+            \\dot{y} = f(t,y), \\quad y(t_0) = y_0.
             
         LSODAR automatically switches between using an ADAMS method
         or an BDF method and is also able to monitor events.

src/solvers/runge_kutta.py

@@ -753,7 +753,7 @@ class RungeKutta4(Explicit_ODE):
     
     .. math::
 
-        \dot{y} = f(t,y), \quad y(t_0) = y_0 .
+        \\dot{y} = f(t,y), \\quad y(t_0) = y_0 .
         
     Using a Runge-Kutta method of order 4, the approximation is defined as 
     follow,