fix typo indicated in #234 (#295)

Signed-off-by: Antonio Santos Izaguirre <antoniosanct@gmail.com>
Co-authored-by: Lukas Jungmann <lukas.jungmann@oracle.com>

api/src/main/java/jakarta/xml/bind/annotation/XmlElementDecl.java

@@ -157,17 +157,17 @@
      * This specifies the namespace name of the XML element whose local
      * name is specified by {@code substitutionHeadName()}.
      * <p>
-     * If {@code susbtitutionHeadName()} is "", then this
+     * If {@code substitutionHeadName()} is "", then this
      * value can only be "##default". But the value is ignored
-     * since this element is not part of susbtitution group when the
-     * value of {@code susbstitutionHeadName()} is "".
+     * since this element is not part of substitution group when the
+     * value of {@code substitutionHeadName()} is "".
      * <p>
-     * If {@code susbtitutionHeadName()} is not "" and the value is
+     * If {@code substitutionHeadName()} is not "" and the value is
      * "##default", then the namespace name is the namespace name to
      * which the package of the containing class, marked with {@link
      * XmlRegistry }, is mapped.
      * <p>
-     * If {@code susbtitutionHeadName()} is not "" and the value is
+     * If {@code substitutionHeadName()} is not "" and the value is
      * not "##default", then the value is the namespace name.
      *
      * @see #substitutionHeadName()

api/src/main/java/jakarta/xml/bind/annotation/XmlElementRef.java

@@ -144,7 +144,7 @@
  * that doesn't have {@link XmlRootElement}. But they can't show up in an
  * XML instance (because they don't have XML element names).
  *
- * <p><b>Example 2: XML Schema Susbstitution group support</b>
+ * <p><b>Example 2: XML Schema Substitution group support</b>
  * <p> The following example shows the annotations for XML Schema
  * substitution groups.  The annotations and the ObjectFactory are
  * derived from the schema.