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/node/compare.jl

@@ -1,15 +1,35 @@
+"""
+    ==(e1::Edge, e2::Edge)
+
+Equality comparison between two edges.
+"""
 function ==(e1::Edge, e2::Edge)
     return e1.edge[1] == e2.edge[1] && e1.edge[2] == e2.edge[2]
 end
 
+"""
+    ==(n1::Node, n2::Node)
+
+Fallback equality comparison between two nodes. For equal node types, the more specific versions of this function will be called.
+"""
 function ==(n1::Node, n2::Node)
     return false
 end
 
+"""
+    ==(n1::ComputeTaskNode, n2::ComputeTaskNode)
+
+Equality comparison between two [`ComputeTaskNode`](@ref)s.
+"""
 function ==(n1::ComputeTaskNode, n2::ComputeTaskNode)
     return n1.id == n2.id
 end
 
+"""
+    ==(n1::DataTaskNode, n2::DataTaskNode)
+
+Equality comparison between two [`DataTaskNode`](@ref)s.
+"""
 function ==(n1::DataTaskNode, n2::DataTaskNode)
     return n1.id == n2.id
 end