Fixed missing types in javadoc.

src/main/java/org/apache/commons/math4/geometry/partitioning/BSPTree.java

@@ -520,6 +520,7 @@ public class BSPTree<S extends Space> {
      * specifies how to handle this situation.
      * setting
      * </p>
+     * @param <S> Type of the space.
      * @since 3.4
      */
     public interface VanishingCutHandler<S extends Space> {

src/main/java/org/apache/commons/math4/linear/FieldLUDecomposition.java

@@ -256,7 +256,9 @@ public class FieldLUDecomposition<T extends FieldElement<T>> {
         return new Solver<T>(field, lu, pivot, singular);
     }
 
-    /** Specialized solver. */
+    /** Specialized solver.
+     * @param <T> the type of the field elements
+     */
     private static class Solver<T extends FieldElement<T>> implements FieldDecompositionSolver<T> {
 
         /** Field to which the elements belong. */

src/main/java/org/apache/commons/math4/stat/Frequency.java

@@ -626,6 +626,7 @@ public class Frequency implements Serializable {
     /**
      * A Comparator that compares comparable objects using the
      * natural order.  Copied from Commons Collections ComparableComparator.
+     * @param <T> the type of the objects compared
      */
     private static class NaturalComparator<T extends Comparable<T>> implements Comparator<Comparable<T>>, Serializable {