docs(specs): make defer semantics on break/continue/return exits explicit

The Defer section only said 'when the enclosing scope block exits', which
left the break/continue paths implicit — the exact ambiguity issue 0108
hid behind. State all three exit kinds and the break/continue-outside-loop
diagnostic.

specs.md

@@ -2257,6 +2257,12 @@ A variable declaration (`name :=`) inside an inner scope shadows any variable wi
 // prints: first, then second
 ```
 
+`break` and `continue` exit the loop body's scope: the iteration's pending
+defers run (LIFO, including entries from nested blocks between the loop and
+the jump) before control transfers — exactly as on the fall-through end of an
+iteration. `return` runs all pending defers of the function. A `break` or
+`continue` outside a loop is a compile-time error.
+
 ---
 
 ## 7. Built-in Functions