fix typos

Signed-off-by: allencloud <allen.sun@daocloud.io>

docs/registry.go

@@ -114,7 +114,7 @@ func DockerHeaders(userAgent string, metaHeaders http.Header) []transport.Reques
 	return modifiers
 }
 
-// HTTPClient returns a HTTP client structure which uses the given transport
+// HTTPClient returns an HTTP client structure which uses the given transport
 // and contains the necessary headers for redirected requests
 func HTTPClient(transport http.RoundTripper) *http.Client {
 	return &http.Client{

docs/session.go

@@ -95,7 +95,7 @@ func cloneRequest(r *http.Request) *http.Request {
 	return r2
 }
 
-// RoundTrip changes a HTTP request's headers to add the necessary
+// RoundTrip changes an HTTP request's headers to add the necessary
 // authentication-related headers
 func (tr *authTransport) RoundTrip(orig *http.Request) (*http.Response, error) {
 	// Authorization should not be set on 302 redirect for untrusted locations.

docs/types.go

@@ -29,7 +29,7 @@ type ImgData struct {
 // indicates the registry's version and whether the registry claims to be a
 // standalone registry.
 type PingResult struct {
-	// Version is the registry version supplied by the registry in a HTTP
+	// Version is the registry version supplied by the registry in an HTTP
 	// header
 	Version string `json:"version"`
 	// Standalone is set to true if the registry indicates it is a