Add inspection to move the variable declaration into when

#KT-29001 Fixed

idea/testData/inspectionsLocal/moveVariableDeclarationIntoWhen/.inspection

@@ -0,0 +1 @@
+org.jetbrains.kotlin.idea.inspections.MoveVariableDeclarationIntoWhenInspection

idea/testData/inspectionsLocal/moveVariableDeclarationIntoWhen/notApplicableOtherName.kt

@@ -0,0 +1,11 @@
+// PROBLEM: none
+fun foo() {
+    val a = 1
+    val b<caret> = 1
+    when (a) {
+        1 -> {
+        }
+        else -> {
+        }
+    }
+}

idea/testData/inspectionsLocal/moveVariableDeclarationIntoWhen/notApplicableSideEffect.kt

@@ -0,0 +1,11 @@
+// PROBLEM: none
+fun foo() {
+    val a<caret> = 1
+    val b = 42
+    when (a) {
+        1 -> {
+        }
+        else -> {
+        }
+    }
+}

idea/testData/inspectionsLocal/moveVariableDeclarationIntoWhen/notApplicableUsedInOtherScope.kt

@@ -0,0 +1,11 @@
+// PROBLEM: none
+fun foo() {
+    val a<caret> = 1
+    when (a) {
+        1 -> {
+        }
+        else -> {
+        }
+    }
+    val b = a
+}

idea/testData/inspectionsLocal/moveVariableDeclarationIntoWhen/notApplicableVar.kt

@@ -0,0 +1,10 @@
+// PROBLEM: none
+fun foo() {
+    var a<caret> = 1
+    when (a) {
+        1 -> {
+        }
+        else -> {
+        }
+    }
+}

idea/testData/inspectionsLocal/moveVariableDeclarationIntoWhen/simple.kt

@@ -0,0 +1,9 @@
+fun test() = 42
+
+fun foo() {
+    val a<caret> = test()
+    when (a) {
+        1 -> a
+        else -> 24
+    }
+}

idea/testData/inspectionsLocal/moveVariableDeclarationIntoWhen/simple.kt.after

@@ -0,0 +1,8 @@
+fun test() = 42
+
+fun foo() {
+    when (val a = test()) {
+        1 -> a
+        else -> 24
+    }
+}

idea/testData/inspectionsLocal/moveVariableDeclarationIntoWhen/withComment.kt

@@ -0,0 +1,11 @@
+fun foo() {
+    val a<caret> = 1
+
+    // comment
+    when (a) {
+        1 -> {
+        }
+        else -> {
+        }
+    }
+}

idea/testData/inspectionsLocal/moveVariableDeclarationIntoWhen/withComment.kt.after

@@ -0,0 +1,10 @@
+fun foo() {
+
+    // comment
+    when (val a = 1) {
+        1 -> {
+        }
+        else -> {
+        }
+    }
+}

idea/testData/inspectionsLocal/moveVariableDeclarationIntoWhen/withNewLine.kt

@@ -0,0 +1,11 @@
+fun foo() {
+    val a<caret> = 1
+
+
+    when (a) {
+        1 -> {
+        }
+        else -> {
+        }
+    }
+}

idea/testData/inspectionsLocal/moveVariableDeclarationIntoWhen/withNewLine.kt.after

@@ -0,0 +1,10 @@
+fun foo() {
+
+
+    when (val a = 1) {
+        1 -> {
+        }
+        else -> {
+        }
+    }
+}