Merge pull request #262 from termi-official/do/fix-pide-docs

Fix PIDE docs

Author: xtalax

docs/src/tutorials/PIDE.md

@@ -3,21 +3,28 @@
 It is also possible to solve PIDEs with MethodOfLines.jl. 
 
 Consider the following system:
+
 ```math
  \frac{\partial}{\partial t}u(t, x)+2u(t, x)+5\frac{\partial}{\partial x}[\int_0^xu(t, x)dx]=1
 ```
+
 On the domain:
+
 ```math
  t \in (0, 2)
  x \in (0, 2\pi)
 ```
+
 With BCs and ICs:
+
 ```math
  u(0, x)=cos(x)
  \frac{\partial}{\partial x}u(t, 0)=0
  \frac{\partial}{\partial x}u(t, 2)=0
 ```
+
 We can discretize such a system like this:
+
 ```@example pide
 using MethodOfLines, ModelingToolkit, OrdinaryDiffEq, DomainSets, Plots
 
@@ -92,4 +99,4 @@ tdisc = sol[t]
 integralsol = sol[integral(t, x)]
 
 heatmap(integralsol)
-```
+```