feat: Drop Signale#toggle without initial boolean value.

Author: teletha

src/main/java/kiss/Signal.java

@@ -3747,18 +3747,6 @@ public final Signal<V> timeout(long time, TimeUnit unit, ScheduledExecutorServic
         });
     }
 
-    /**
-     * <p>
-     * Returns an {@link Signal} that applies the boolean values alternately to each item emitted by
-     * an {@link Signal} and emits the result. Initial value is true.
-     * </p>
-     *
-     * @return {ChainableAPI}
-     */
-    public final Signal<Boolean> toggle() {
-        return toggle(true);
-    }
-
     /**
      * <p>
      * Returns an {@link Signal} that applies the boolean values alternately to each item emitted by

src/test/java/kiss/signal/ToggleTest.java

@@ -15,7 +15,7 @@ class ToggleTest extends SignalTester {
 
     @Test
     void trueOrFalse() {
-        monitor(String.class, boolean.class, signal -> signal.toggle());
+        monitor(String.class, boolean.class, signal -> signal.toggle(true));
 
         assert main.emit("first value is true").value(true);
         assert main.emit("second value is false").value(false);
@@ -78,7 +78,7 @@ void acceptNull() {
 
     @Test
     void error() {
-        monitor(boolean.class, signal -> signal.toggle());
+        monitor(boolean.class, signal -> signal.toggle(true));
 
         assert main.emit(Error).value();
         assert main.isNotCompleted();
@@ -88,7 +88,7 @@ void error() {
 
     @Test
     void complete() {
-        monitor(boolean.class, signal -> signal.toggle());
+        monitor(boolean.class, signal -> signal.toggle(true));
 
         assert main.emit(Complete).value();
         assert main.isCompleted();