KT-759 Filter keywords auto completion according to context

idea/testData/completion/handlers/PropertiesSetter.kt

@@ -0,0 +1,4 @@
+class TestClass {
+    val a : Int
+        ge<caret>
+}

idea/testData/completion/handlers/PropertiesSetter.kt.after

@@ -0,0 +1,4 @@
+class TestClass {
+    val a : Int
+        get()<caret>
+}