refactor: the long goodbye

long is 32 bits on windows, while it is 64 bits on other architectures.
This makes the type suboptimal for a codebase meant to be
cross-platform. Replace it with more appropriate integer types.

src/nvim/ex_session.c

@@ -629,7 +629,7 @@ static int makeopens(FILE *fd, char *dirnow)
         && buf->b_p_bl) {
       if (fprintf(fd, "badd +%" PRId64 " ",
                   buf->b_wininfo == NULL
-                  ? (int64_t)1L
+                  ? 1
                   : (int64_t)buf->b_wininfo->wi_mark.mark.lnum) < 0
           || ses_fname(fd, buf, &ssop_flags, true) == FAIL) {
         return FAIL;