Revert "eolian: inherit since information from struct to field"

This reverts commit f349510941.

This patch is causing some "ninja test" errors, so the errors
should be fixed first.

src/lib/eolian/eo_parser.c

@@ -536,8 +536,6 @@ parse_struct(Eo_Lexer *ls, const char *name, Eina_Bool is_extern,
 qual_end:
         check_next(ls, ';');
         FILL_DOC(ls, fdef, doc);
-        if (def->doc && fdef->doc && def->doc->since && !fdef->doc->since)
-          fdef->doc->since = eina_stringshare_ref (def->doc->since);
      }
    check_match(ls, '}', '{', bline, bcolumn);
    FILL_BASE(def->base, ls, line, column, TYPEDECL);