fix std hover, full capture terminator, bare static calls, void main in run-only images

- hover: a symbol from an embedded library source (tinyvm:std.zc, tinyvm:icon.zc) was
  looked up only in the document; look it up by its qualified name in the library source
  (hover_embedded_sym), and render a method found that way by its line (bs_hover).
- std.capture: allocate one word more than the 256 it holds, so end() terminates inside the buffer.
- a bare call to a static function of the enclosing struct resolves like a bare struct constant
  (mstruct is set for every non-generic struct's methods); the struct's own wins over a global.
- run.zc declares main untyped (fn main();), so a run-only image accepts int, void or untyped main
  with both compilers.

1 files changed, 3 insertions, 2 deletions

diff --git a/src/runtime/run.zc b/src/runtime/run.zc
index a8f82e2..19a5234 100644
--- a/src/runtime/run.zc
+++ b/src/runtime/run.zc
@@ -8,9 +8,10 @@ include rt;
 //
 //   cat build/run/rt.zc src/runtime/run.zc examples/hello.zc | ./zc0 >build/run/genome.h
 
-// the program's entry point, written by the program (see start).
+// the program's entry point, written by the program (see start). the prototype is untyped so
+// that main may be declared int, void or untyped, as in any other program: its value is ignored.
 namespace;
-int main();
+fn main();
 namespace run;
 include rt;