change signature detection: ignore changes in return type when no other changes were made; include new return type in result change info; leave suggestion when method become unused due to return type deletion

java/java-tests/testData/refactoring/changeSignatureGesture/AddParamChangeReturnType.java

@@ -0,0 +1,8 @@
+class Test {
+  void foo() {
+    bar();
+  }
+
+  void bar(<caret>){
+  }
+}

java/java-tests/testData/refactoring/changeSignatureGesture/AddParamChangeReturnType_after.java

@@ -0,0 +1,8 @@
+class Test {
+  void foo() {
+    bar();
+  }
+
+  boolean bar(int param){
+  }
+}

java/java-tests/testData/refactoring/changeSignatureGesture/AddParameter2Constructor.java

@@ -0,0 +1,9 @@
+package refactoring.changeSignatureGesture;
+class TestMeabracadabra {
+  TestMeabracadabra(<caret>){
+  }
+
+  public static void main(String[] args) {
+    TestMeabracadabra t = new TestMeabracadabra();
+  }
+}

java/java-tests/testData/refactoring/changeSignatureGesture/AddParameter2Constructor_after.java

@@ -0,0 +1,9 @@
+package refactoring.changeSignatureGesture;
+class TestMeabracadabra {
+  TestMeabracadabra(int param){
+  }
+
+  public static void main(String[] args) {
+    TestMeabracadabra t = new TestMeabracadabra();
+  }
+}

java/java-tests/testData/refactoring/changeSignatureGesture/AddParameter2UnusedConstructor.java

@@ -0,0 +1,5 @@
+package refactoring.changeSignatureGesture;
+class TestMeabracadabra {
+  private TestMeabracadabra(<caret>){
+  }
+}