evaluation does not always begin at a root schema resource

for example, if we start evaluating at "https://foo.com/schema.json#/$defs/Foo" and /$defs/Foo does not contain an $id keyword

Author: karenetheridge

jsonschema-core.xml

@@ -655,8 +655,9 @@
                 </t>
                 <t>
                     Other keywords may take into account the dynamic scope that exists during the
-                    evaluation of a schema.  The outermost dynamic scope is the root schema of the
-                    schema document in which processing begins.  The path from this root schema to
+                    evaluation of a schema. The outermost dynamic scope is the schema object at
+                    which processing begins, even if it is not a schema resource root.
+                    The path from this schema to
                     any particular keyword (that includes any "$ref" and "$dynamicRef" keywords that
                     may have been resolved) is considered the keyword's "validation path."
                 </t>