more forward declarations

specs.md

@@ -951,9 +951,9 @@ main :: () {
   // void return, no -> annotation
 }
 
-// Bare-block shorthand (equivalent to no-arg void function):
-main :: {
-  // same as main :: () { ... }
+// No-arg void function:
+main :: () {
+  // ...
 }
 ```
 
@@ -1468,7 +1468,7 @@ compute :: (x: s32) -> s32 {
 Bare blocks can be used as statements to introduce a new lexical scope. Variables declared inside a scope block are local to that block. No trailing `;` is required.
 
 ```sx
-main :: {
+main :: () {
   x := 42;
   {
     x := 6;                        // shadows outer x