Minor updates to comments

src/main/java/com/github/psambit9791/jdsp/filter/_FrequencyFilter.java

@@ -20,6 +20,7 @@
  * @version 1.1
  */
 public interface _FrequencyFilter {
+
     /**
      * This method implements a low pass filter with given parameters, filters the signal and returns it.
      * @param order Order of the filter

src/main/java/com/github/psambit9791/jdsp/filter/_KernelFilter.java

@@ -22,7 +22,7 @@
  */
 public interface _KernelFilter {
     /**
-     * This method implements a filter with given parameters, applies it on the signal and returns it.
+     * This method implements a kernel filter with given parameters, applies it on the signal and returns it.
      * @return double[] Filtered signal
      */
     public double[] filter();