Introduce "use expression body" inspection #KT-16063 Fixed

Converted from the relevant intention
Reported cases: one-liners, whens
Also, more exact caret detection in local inspection tests

idea/testData/quickfix/override/overridingOpenMethodInFinalClass.kt

@@ -1,5 +1,4 @@
 // "Make A.foo open" "false"
-// ACTION: Convert to expression body
 // ERROR: This type is final, so it cannot be inherited from
 class A() {
     open fun foo() {}