Improve warnings from native compiler

* src/comp.c (syms_of_comp) <native-compiler>: Rename from 'comp'.

* src/lread.c (maybe_swap_for_eln):
* lisp/emacs-lisp/comp.el (comp--fwprop):
* lisp/emacs-lisp/comp-run.el
(comp--accept-and-process-async-output, native--compile-async):
Adjust to the new symbol.

lisp/emacs-lisp/comp.el

@@ -2792,7 +2792,7 @@ Return t if something was changed."
                   finally
                   (when (= i 100)
                     (display-warning
-                     'comp
+                     'native-compiler
                      (format "fwprop pass jammed into %s?" (comp-func-name f))))
                   (comp-log (format "Propagation run %d times\n" i) 2))
                  (comp--rewrite-non-locals)