Add commentary about inserting type for lateinit var in completion

- Also, use dedicated method to check modifier

idea/idea-completion/src/org/jetbrains/kotlin/idea/completion/BasicCompletionSession.kt

@@ -189,7 +189,9 @@ class BasicCompletionSession(
                 completeDeclarationNameFromUnresolvedOrOverride(declaration)
 
                 if (declaration is KtProperty) {
-                    completeParameterOrVarNameAndType(declaration.modifierList?.hasModifier(KtTokens.LATEINIT_KEYWORD) == true)
+                    // we want to insert type only if the property is lateinit,
+                    // because lateinit var cannot have its type deduced from initializer
+                    completeParameterOrVarNameAndType(withType = declaration.hasModifier(KtTokens.LATEINIT_KEYWORD))
                 }
 
                 // no auto-popup on typing after "val", "var" and "fun" because it's likely the name of the declaration which is being typed by user