Add documentation to every function and automatic doc html building (#6)

Reviewed-on: Rubydragon/MetagraphOptimization.jl#6
Co-authored-by: Anton Reinhard <anton.reinhard@proton.me>
Co-committed-by: Anton Reinhard <anton.reinhard@proton.me>

src/diff/print.jl

@@ -1,3 +1,8 @@
+"""
+    show(io::IO, diff::Diff)
+
+Pretty-print a [`Diff`](@ref). Called via print, println and co.
+"""
 function show(io::IO, diff::Diff)
     print(io, "Nodes: ")
     print(io, length(diff.addedNodes) + length(diff.removedNodes))

src/diff/properties.jl

@@ -1,4 +1,9 @@
-# return a namedtuple of the lengths of the added/removed nodes/edges
+"""
+    length(diff::Diff)
+    
+Return a named tuple of the lengths of the added/removed nodes/edges.
+The fields are `.addedNodes`, `.addedEdges`, `.removedNodes` and `.removedEdges`.
+"""
 function length(diff::Diff)
     return (
         addedNodes = length(diff.addedNodes),

src/diff/type.jl

@@ -1,3 +1,8 @@
+"""
+    Diff
+
+A named tuple representing a difference of added and removed nodes and edges on a [`DAG`](@ref).
+"""
 const Diff = NamedTuple{
     (:addedNodes, :removedNodes, :addedEdges, :removedEdges),
     Tuple{Vector{Node}, Vector{Node}, Vector{Edge}, Vector{Edge}},