Move delayedInit.md to dropped subdirectory

Author: odersky

docs/docs/reference/delaydInit.md renamed to docs/docs/reference/dropped/delayedInit.md

@@ -6,7 +6,7 @@ sidebar:
         - title: Dropped Features
           subsection:
             - title: DelayedInit
-            - url: docs/reference/delayed-init.md
+              url: docs/reference/dropped/delayed-init.md
         - title: Implicit Function Types
           url: docs/reference/implicit-function-types.md
         - title: Intersection types