Correct the SetHint docs and return an error if the hint value is an multi-key map.

Author: matthewdale

mongo/collection.go

@@ -1282,6 +1282,9 @@ func (coll *Collection) Distinct(
 		op.Comment(comment)
 	}
 	if args.Hint != nil {
+		if isUnorderedMap(args.Hint) {
+			return &DistinctResult{err: ErrMapForOrderedArgument{"hint"}}
+		}
 		hint, err := marshalValue(args.Hint, coll.bsonOpts, coll.registry)
 		if err != nil {
 			return &DistinctResult{err: err}

mongo/options/distinctoptions.go

@@ -62,10 +62,14 @@ func (do *DistinctOptionsBuilder) SetComment(comment interface{}) *DistinctOptio
 	return do
 }
 
-// SetHint sets the value for the Comment field. Specifies a string or document that
-// will be included in server logs, profiling logs, and currentOp queries to help trace
-// the operation. The default value is nil, which means that no comment will be included
-// in the logs.
+// SetHint specifies the index to use for the operation. This should either be
+// the index name as a string or the index specification as a document. This
+// option is only valid for MongoDB versions >= 7.1. Previous server versions
+// will return an error if an index hint is specified. Distinct returns an error
+// if the hint parameter is a multi-key map. The default value is nil, which
+// means that no index hint will be sent.
+//
+// SetHint sets the Hint field.
 func (do *DistinctOptionsBuilder) SetHint(hint interface{}) *DistinctOptionsBuilder {
 	do.Opts = append(do.Opts, func(opts *DistinctOptions) error {
 		opts.Hint = hint