Introduce inspection for unused main parameter #KT-26999 Fixed

idea/testData/inspectionsLocal/unusedMainParameter/.inspection

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

idea/testData/inspectionsLocal/unusedMainParameter/future.kt

@@ -0,0 +1,6 @@
+// PROBLEM: none
+// LANGUAGE_VERSION: 1.4
+
+fun main(<caret>args: Array<String>) {
+
+}

idea/testData/inspectionsLocal/unusedMainParameter/legacy.kt

@@ -0,0 +1,6 @@
+// PROBLEM: none
+// LANGUAGE_VERSION: 1.2
+
+fun main(<caret>args: Array<String>) {
+
+}

idea/testData/inspectionsLocal/unusedMainParameter/simple.kt

@@ -0,0 +1,5 @@
+// LANGUAGE_VERSION: 1.3
+
+fun main(<caret>args: Array<String>) {
+
+}

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

@@ -0,0 +1,5 @@
+// LANGUAGE_VERSION: 1.3
+
+fun main() {
+
+}