Correct PARSE_UNQUALIFIED_NAMES example output

+ Add input/output

Author: mrotteveel

doc/sql.extensions/README.sql_package.md

@@ -48,15 +48,21 @@ select *
 `RDB$SQL.PARSE_UNQUALIFIED_NAMES` is a selectable procedure that parses a list of unqualified SQL names and returns
 one row for each name. The input must follow parse rules for names and the output of unquoted names are uppercased.
 
+Input parameters:
+- `NAMES` type `RDB$TEXT_MAX` - list of names
+
+Output parameters
+- `NAME` type `RDB$RELATION_NAME` - a single name, normalised to how identifiers are stored in the metadata tables
+
 ```sql
 select *
   from rdb$sql.parse_unqualified_names('schema1, schema2, "schema3", "schema 4", "schema ""5"""');
 
 -- SCHEMA1
 -- SCHEMA2
 -- schema3
--- "schema 4"
--- "schema "5"
+-- schema 4
+-- schema "5"
 ```
 
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