Add \left and \right to TeX parentheses in brusselator.md

Author: abhro

docs/src/showcase/brusselator.md

@@ -29,8 +29,8 @@ The Brusselator PDE is defined as follows:
 
 ```math
 \begin{align}
-\frac{\partial u}{\partial t} &= 1 + u^2v - 4.4u + \alpha(\frac{\partial^2 u}{\partial x^2} + \frac{\partial^2 u}{\partial y^2}) + f(x, y, t)\\
-\frac{\partial v}{\partial t} &= 3.4u - u^2v + \alpha(\frac{\partial^2 v}{\partial x^2} + \frac{\partial^2 v}{\partial y^2})
+\frac{\partial u}{\partial t} &= 1 + u^2v - 4.4u + \alpha \left(\frac{\partial^2 u}{\partial x^2} + \frac{\partial^2 u}{\partial y^2}\right) + f(x, y, t)\\
+\frac{\partial v}{\partial t} &= 3.4u - u^2v + \alpha \left(\frac{\partial^2 v}{\partial x^2} + \frac{\partial^2 v}{\partial y^2}\right)
 \end{align}
 ```