fixed grammar type in code and Documentation

src/main/java/org/codehaus/groovy/runtime/metaclass/MetaClassRegistryImpl.java

@@ -413,7 +413,7 @@ protected void fireConstantMetaClassUpdate(Object obj, Class c, final MetaClass
     }
 
     /**
-     * Gets an array of of all registered ConstantMetaClassListener instances.
+     * Gets an array of all registered ConstantMetaClassListener instances.
      */
     @Override
     public MetaClassRegistryChangeEventListener[] getMetaClassRegistryChangeEventListeners() {

src/spec/doc/core-operators.adoc

@@ -579,7 +579,7 @@ it will return null instead of throwing a `NullPointerException`:
 ----
 include::../test/OperatorsTest.groovy[tags=spreaddot_nullsafe,indent=0]
 ----
-<1> build a list for which of of the elements is `null`
+<1> build a list for which one of the elements is `null`
 <2> using the spread operator will *not* throw a `NullPointerException`
 <3> the receiver might also be null, in which case the return value is `null`
 

subprojects/groovy-swing/src/main/java/org/apache/groovy/swing/extensions/SwingExtensions.java

@@ -224,7 +224,7 @@ public static DefaultListModel<?> leftShift(DefaultListModel<Object> self, Objec
      * Allow DefaultListModel to work with subscript operators.<p>
      * <b>WARNING:</b> this operation does not replace the element at the
      * specified index, rather it inserts the element at that index, thus
-     * increasing the size of of the model by 1.
+     * increasing the size of the model by 1.
      *
      * @param self  a DefaultListModel
      * @param index an index

subprojects/groovy-xml/src/main/java/groovy/xml/DOMBuilder.java

@@ -229,7 +229,7 @@ protected void appendNamespaceAttributes(Element element, Map<Object, Object> at
                 QName qname = (QName) key;
                 element.setAttributeNS(qname.getNamespaceURI(), qname.getQualifiedName(), value.toString());
             } else {
-                throw new IllegalArgumentException("The key: " + key + " should be an instanceof of " + QName.class);
+                throw new IllegalArgumentException("The key: " + key + " should be an instance of " + QName.class);
             }
         }
     }