Merge pull request #280 from SciML/ChrisRackauckas-patch-1

Update operator_algebras.md

Author: ChrisRackauckas

docs/src/tutorials/operator_algebras.md

@@ -1,4 +1,4 @@
-## [Demonstration of Operator Algebras and Kron](@id operator_algebras)
+# [Demonstration of Operator Algebras and Kron](@id operator_algebras)
 
 Let `M`, `D`, `F` be matrix-based, diagonal-matrix-based, and function-based
 `SciMLOperators` respectively. Here are some examples of composing operators
@@ -56,4 +56,4 @@ L4 = cache_operator(L4, u)
 # allocation-free evaluation
 L2(w, v, u, p, t) # == mul!(w, L2, v)
 L4(w, v, u, p, t, α, β) # == mul!(w, L4, v, α, β)
-```
+```