Determine Better Equality Rules for `ConfigurationNode`

[Sparky983]

Motivation

#63 is adds diffs like this:

-    when(deserializer.deserialize(eq(node), any())).thenReturn(renderer);
+    final ArgumentMatcher<ConfigurationNode> isValue =
+        arg -> {
+          try {
+            return arg.asString().equals("value");
+          } catch (final DeserializationException e) {
+            return false;
+          }
+        };
+    when(deserializer.deserialize(argThat(isValue), any())).thenReturn(renderer);

which is not ideal as ConfigurationNode.string("value") should be equivalent to a scalar with the value "value".

(IIRC) a lot of the tests depend on this optimisation:

        switch (nodes.size()) {
          /* ... */
          case 1 -> nodes.get(0);
          default -> new CompositeNode(nodes);
        };

that will avoid the creation of a CompositeNode if there is only a single node. This behaviour shouldn't be observable through regular uses of the API such as in tests.

Description

I'm thinking that, in order to hold up the Object::equals contract, if any representations are equal, two nodes themselves are should be considered equal.

This would mean that all the following pairs are all equal:

CompositeNode(ConfigurationNode.string("abc"))
ConfigurationNode.string("abc")

CompositeNode(ConfigurationNode.integer(10), ConfigurationNode.string("abc"))
ConfigurationNode.integer(10)

CompositeNode(
    ConfigurationNode.list(
        ConfigurationNode.integer(10)
    ), 
    ConfigurationNode.string("abc")
)
ConfigurationNode.list(ConfigurationNode.integer(10))

ConfigurationNode.list(
    CompositeNode(
        ConfigurationNode.string("abc"),
        ConfigurationNode.integer(10)
    )
)
ConfigurationNode.list(ConfigurationNode.integer(10))

Alternatives

Alternatively, equality could be defined as two nodes with have the same representations and each representation is equal.

This would mean ConfigurationNode.integer(10) != YamlScalarConfigurationNode("10") because the YamlScalarConfigurationNode represents both the string "10" and the integer 10 whereas the ConfigurationNode.integer represents only the integer 10.