Add spacing

Author: abhro

src/diff.jl

@@ -170,13 +170,13 @@ and other derivative rules to expand any derivatives it encounters.
 ```jldoctest
 julia> @variables x y z k;
 
-julia> f=k*(abs(x-y)/y-z)^2
+julia> f = k*(abs(x-y)/y-z)^2
 k*((abs(x - y) / y - z)^2)
 
-julia> Dx=Differential(x) # Differentiate wrt x
+julia> Dx = Differential(x) # Differentiate wrt x
 (::Differential) (generic function with 2 methods)
 
-julia> dfx=expand_derivatives(Dx(f))
+julia> dfx = expand_derivatives(Dx(f))
 (k*((2abs(x - y)) / y - 2z)*IfElse.ifelse(signbit(x - y), -1, 1)) / y
 ```
 """

src/rewrite-helpers.jl

@@ -1,5 +1,6 @@
 """
-replacenode(expr::Symbolic, rules...)
+    replacenode(expr::Symbolic, rules...)
+
 Walk the expression and replacenode subexpressions according to `rules`. `rules`
 could be rules constructed with `@rule`, a function, or a pair where the
 left hand side is matched with equality (using `isequal`) and is replacenoded by the right hand side.
@@ -75,7 +76,8 @@ function _hasnode(r, y)
 end
 
 """
-filterchildren(c, x)
+    filterchildren(c, x)
+
 Returns all parts of `x` that fulfills the condition given in c. c can be a function or an expression.
 If it is a function, returns everything for which the function is `true`. If c is an expression, returns
 all expressions that matches it.