Implement jsonb_validation_errors_detailed to return detailed errors

README.md

@@ -24,6 +24,7 @@ This extension exposes the following four SQL functions:
 - jsonb_matches_schema (note the **jsonb** in front)
 - jsonschema_is_valid
 - jsonschema_validation_errors
+- jsonb_validation_errors_detailed
 
 With the following signatures
 
@@ -53,6 +54,13 @@ and
 jsonschema_validation_errors(schema json, instance json) returns text[]
 ```
 
+and
+
+```sql
+-- Returns an array of errors if a *schema* is invalid
+jsonb_validation_errors_detailed(schema jsonschema, instance jsonb) returns jsonb
+```
+
 ### Compiled schema type
 
 For repeated validation against the same schema, cast it to `jsonschema` once. The validator is compiled and cached per callsite, avoiding recompilation on every row.