Fix and improve Javadoc in spring-oxm

See gh-28796

spring-oxm/src/main/java/org/springframework/oxm/Marshaller.java

@@ -26,7 +26,7 @@ import javax.xml.transform.Result;
  *
  * <p>Although the {@code marshal} method accepts a {@code java.lang.Object} as its
  * first parameter, most {@code Marshaller} implementations cannot handle arbitrary
- * {@code Object}s. Instead, a object class must be registered with the marshaller,
+ * {@code Object}s. Instead, an object class must be registered with the marshaller,
  * or have a common base class.
  *
  * @author Arjen Poutsma

spring-oxm/src/main/java/org/springframework/oxm/support/AbstractMarshaller.java

@@ -488,7 +488,7 @@ public abstract class AbstractMarshaller implements Marshaller, Unmarshaller {
 
 	/**
 	 * Abstract template method for marshalling the given object graph to a DOM {@code Node}.
-	 * <p>In practice, node is be a {@code Document} node, a {@code DocumentFragment} node,
+	 * <p>In practice, {@code node} is a {@code Document} node, a {@code DocumentFragment} node,
 	 * or a {@code Element} node. In other words, a node that accepts children.
 	 * @param graph the root of the object graph to marshal
 	 * @param node the DOM node that will contain the result tree