more nits

google/downscope/downscoping.go

@@ -9,13 +9,13 @@ can use. Please note that only Google Cloud Storage supports this feature.
 For complete documentation, see https://cloud.google.com/iam/docs/downscoping-short-lived-credentials
 
 To downscope permissions of a source credential, you need to define
-a Credential Access Boundary.  Said Boundary specifies which resources
+a Credential Access Boundary. Said Boundary specifies which resources
 the newly created credential can access, an upper bound on the permissions
-it has over those resources, and optionally  attribute-based conditional
+it has over those resources, and optionally attribute-based conditional
-access to the aforementioned resources.  For more information on IAM
+access to the aforementioned resources. For more information on IAM
 Conditions, see https://cloud.google.com/iam/docs/conditions-overview.
 
-This functionality would typically be used to provide a third party with
+This functionality can be used to provide a third party with
 limited access to and permissions on resources held by the owner of the root
 credential or internally in conjunction with the principle of least privilege
 to ensure that internal services only hold the minimum necessary privileges
@@ -185,7 +185,7 @@ func (dts downscopingTokenSource) Token() (*oauth2.Token, error) {
 		if err != nil {
 			return nil, fmt.Errorf("downscope: unable to exchange token; %v. Failed to read response body: %v", resp.StatusCode, err)
 		}
-		return nil, fmt.Errorf("downscope: unable to exchange token; %v.  Server responsed: %v", resp.StatusCode, string(b))
+		return nil, fmt.Errorf("downscope: unable to exchange token; %v. Server responsed: %v", resp.StatusCode, string(b))
 	}
 
 	var tresp downscopedTokenResponse

google/downscope/tokenbroker_test.go

@@ -18,7 +18,9 @@ func ExampleNewTokenSource() {
 	// This shows how to generate a downscoped token. This code would be run on the
 	// token broker, which holds the root token used to generate the downscoped token.
 	ctx := context.Background()
-	// Initializes an accessBoundary with one Rule.
+	// Initializes an accessBoundary with one Rule which restricts the downscoped
+	// token to only be able to access the bucket "foo" and only grants it the
+	// permission "storage.objectViewer".
 	accessBoundary := []downscope.AccessBoundaryRule{
 		{
 			AvailableResource:    "//storage.googleapis.com/projects/_/buckets/foo",

google/downscope/tokenconsumer_test.go

@@ -11,7 +11,7 @@ type localTokenSource struct {
 
 func (localTokenSource) Token() (*oauth2.Token, error) {
 	var remoteToken oauth2.Token
-	// retrieve remoteToken, an oauth2.Token, from token broker
+	// Retrieve remoteToken, an oauth2.Token, from token broker
 	return &remoteToken, nil
 }
 
@@ -26,13 +26,13 @@ func Example() {
 		brokerURL:       "yourURL.com/internal/broker",
 	}
 
-	// Wrap the TokenSource in an oauth2.ReuseTokenSource to enable automatic refreshing
+	// Wrap the TokenSource in an oauth2.ReuseTokenSource to enable automatic refreshing.
 	refreshableTS := oauth2.ReuseTokenSource(nil, thisTokenSource)
 
 	// You can now use the token source to access Google Cloud Storage resources as follows.
 
 	// storageClient, err := storage.NewClient(ctx, option.WithTokenSource(refreshableTS))
-	// bkt := storageClient.Bucket("foo"")
+	// bkt := storageClient.Bucket("foo")
 	// obj := bkt.Object(objectName)
 	// rc, err := obj.NewReader(ctx)
 	// defer rc.Close()