(GH-538) Return Schema for subschema extension methods

This change:

- Updates the following functions to return instances of `schemars::Schema`
  instead of `Map<String, Value>`, since the returned data is _always_ a
  subschema, if it exists:

  - `get_defs_subschema_from_id()`
  - `get_defs_subschema_from_id_mut()`
  - `get_defs_subschema_from_reference()`
  - `get_defs_subschema_from_reference_mut()`
  - `get_property_subschema()`
  - `get_property_subschema_mut()`
- Removes the type aliases `Object` (for `Map<String, Value>`) and `Array`
  (for `Vec<Value>`), as these conveniences weren't saving much typing and
  Rust Analyzer wasn't always plumbing them through for IntelliSense. The
  uses of these aliases now revert to calling the underlying types.
- Updates documentation and tests for the modified functions.

Author: michaeltlombardi

lib/dsc-lib-jsonschema/src/schema_utility_extensions.rs

@@ -344,7 +344,7 @@ pub trait SchemaUtilityExtensions {
     ///     None
     /// )
     /// ```
-    fn get_keyword_as_object(&self, key: &str) -> Option<&Map<String, Value>>;
+    fn get_keyword_as_object(&self, key: &str) -> Option<&Object>;
     /// Checks a JSON Schema for a given keyword and mutably borrows the value of that  keyword,
     /// if it exists, as a [`Map`].
     ///
@@ -395,7 +395,7 @@ pub trait SchemaUtilityExtensions {
     ///     None
     /// )
     /// ```
-    fn get_keyword_as_object_mut(&mut self, key: &str) -> Option<&mut Map<String, Value>>;
+    fn get_keyword_as_object_mut(&mut self, key: &str) -> Option<&mut Object>;
     /// Checks a JSON schema for a given keyword and borrows the value of that keyword, if it
     /// exists, as a [`Number`].
     ///
@@ -800,7 +800,7 @@ pub trait SchemaUtilityExtensions {
     ///     defs_json.as_object()
     /// );
     /// ```
-    fn get_defs(&self) -> Option<&Map<String, Value>>;
+    fn get_defs(&self) -> Option<&Object>;
     /// Retrieves the `$defs` keyword and mutably borrows the object if it exists.
     ///
     /// If the keyword isn't defined or isn't an object, the function returns [`None`].
@@ -828,9 +828,9 @@ pub trait SchemaUtilityExtensions {
     ///     defs_json.as_object_mut()
     /// );
     /// ```
-    fn get_defs_mut(&mut self) -> Option<&mut Map<String, Value>>;
-    /// Looks up a reference in the `$defs` keyword by `$id` and returns the subschema entry as a
-    /// [`Schema`] if it exists.
+    fn get_defs_mut(&mut self) -> Option<&mut Object>;
+    /// Looks up a reference in the `$defs` keyword by `$id` and returns the subschema entry as an
+    /// object if it exists.
     ///
     /// The value for the `id` _must_ be the absolute URL of the target subschema's `$id` keyword.
     /// If the target subschema doesn't define the `$id` keyword, this function can't resolve the
@@ -1107,7 +1107,7 @@ pub trait SchemaUtilityExtensions {
     ///     Some(&mut new_definition)
     /// )
     /// ```
-    fn insert_defs_subschema(&mut self, definition_key: &str, definition_value: &Map<String, Value>) -> Option< Map<String, Value>>;
+    fn insert_defs_subschema(&mut self, definition_key: &str, definition_value: &Object) -> Option<Object>;
     /// Looks up a subschema in the `$defs` keyword by reference and, if it exists, renames the
     /// _key_ for the definition.
     ///
@@ -1177,7 +1177,7 @@ pub trait SchemaUtilityExtensions {
     ///     properties_json.as_object()
     /// );
     /// ```
-    fn get_properties(&self) -> Option<&Map<String, Value>>;
+    fn get_properties(&self) -> Option<&Object>;
     /// Retrieves the `properties` keyword and mutably borrows the object if it exists.
     ///
     /// If the keyword isn't defined or isn't an object, the function returns [`None`].
@@ -1205,7 +1205,7 @@ pub trait SchemaUtilityExtensions {
     ///     properties_json.as_object_mut()
     /// );
     /// ```
-    fn get_properties_mut(&mut self) -> Option<&mut Map<String, Value>>;
+    fn get_properties_mut(&mut self) -> Option<&mut Object>;
     /// Looks up a property in the `properties` keyword by name and returns the subschema entry as
     /// a [`Schema`] if it exists.
     ///
@@ -1292,11 +1292,11 @@ impl SchemaUtilityExtensions for Schema {
         self.get(key)
             .and_then(Value::as_number)
     }
-    fn get_keyword_as_object(&self, key: &str) -> Option<&Map<String, Value>> {
+    fn get_keyword_as_object(&self, key: &str) -> Option<&Object> {
         self.get(key)
             .and_then(Value::as_object)
     }
-    fn get_keyword_as_object_mut(&mut self, key: &str) -> Option<&mut Map<String, Value>> {
+    fn get_keyword_as_object_mut(&mut self, key: &str) -> Option<&mut Object> {
         self.get_mut(key)
             .and_then(Value::as_object_mut)
     }
@@ -1321,10 +1321,10 @@ impl SchemaUtilityExtensions for Schema {
         self.get(key)
             .and_then(Value::as_u64)
     }
-    fn get_defs(&self) -> Option<&Map<String, Value>> {
+    fn get_defs(&self) -> Option<&Object> {
         self.get_keyword_as_object("$defs")
     }
-    fn get_defs_mut(&mut self) -> Option<&mut Map<String, Value>> {
+    fn get_defs_mut(&mut self) -> Option<&mut Object> {
         self.get_keyword_as_object_mut("$defs")
     }
     fn get_defs_subschema_from_id(&self, id: &str) -> Option<&Schema> {
@@ -1468,10 +1468,10 @@ impl SchemaUtilityExtensions for Schema {
         self.insert("$id".to_string(), Value::String(id_uri.to_string()))
             .and(old_id)
     }
-    fn get_properties(&self) -> Option<&Map<String, Value>> {
+    fn get_properties(&self) -> Option<&Object> {
         self.get_keyword_as_object("properties")
     }
-    fn get_properties_mut(&mut self) -> Option<&mut Map<String, Value>> {
+    fn get_properties_mut(&mut self) -> Option<&mut Object> {
         self.get_keyword_as_object_mut("properties")
     }
     fn get_property_subschema(&self, property_name: &str) -> Option<&Schema> {