DOC: optimize.differential_evolution fix newline (#12117)

scipy/optimize/_differentialevolution.py

@@ -195,7 +195,7 @@ def differential_evolution(func, bounds, args=(), strategy='best1bin',
     creating trial candidates, which suit some problems more than others. The
     'best1bin' strategy is a good starting point for many systems. In this
     strategy two members of the population are randomly chosen. Their difference
-    is used to mutate the best member (the `best` in `best1bin`), :math:`b_0`,
+    is used to mutate the best member (the 'best' in 'best1bin'), :math:`b_0`,
     so far:
 
     .. math::
@@ -246,6 +246,7 @@ def differential_evolution(func, bounds, args=(), strategy='best1bin',
     (array([1., 1., 1., 1., 1.]), 1.9216496320061384e-19)
 
     Let's try and do a constrained minimization
+
     >>> from scipy.optimize import NonlinearConstraint, Bounds
     >>> def constr_f(x):
     ...     return np.array(x[0] + x[1])