Update doc for dirver.Connector that implements io.Closer

Author: tie

src/database/sql/driver/driver.go

@@ -116,8 +116,8 @@ type DriverContext interface {
 // access to context and to avoid repeated parsing of driver
 // configuration.
 //
-// If a Connector implements io.Closer interface, the sql package's
-// DB.Close will call the Close method and return the error (if any).
+// If a Connector implements io.Closer, the sql package's DB.Close
+// method will call Close and return error (if any).
 type Connector interface {
 	// Connect returns a connection to the database.
 	// Connect may return a cached connection (one previously