docs: add print() method declaration to PMatrix interface

Author: Sumamasonia

core/src/processing/core/PMatrix.java

@@ -208,7 +208,5 @@ public void preApply(float n00, float n01, float n02, float n03,
   /**
    * Print the matrix data to the console.
    */
-  default void print() {
-    System.out.println(this);
-  }
+  public void print();
 }