Initial implementation of loop-to-call-chain intention

idea/testData/intentions/loopToCallChain/flatMap_notIterable.kt

@@ -0,0 +1,10 @@
+// WITH_RUNTIME
+// IS_APPLICABLE: false
+fun foo(list: List<String>): Char? {
+    <caret>for (s in list) {
+        for (c in s) {
+            if (c != ' ') return c
+        }
+    }
+    return null
+}