format headers

We move `tmp/format-headers.sh` into `bin/format-headers.sh`.

We also add a few missing empty lines to `README.md`.

We add `bin/format-headers.sh` to the `bin/README.md`.

We run `bin/format-headers.sh` to perform the above.

Performed `make www` to accomplish the above and to test under macOS.

1986/wall/README.md

@@ -27,6 +27,7 @@ supports the `-traditional-cpp` option.
         make alt
 ```
 
+
 ### Alternate use:
 
 Use `wall.alt` as you would `wall` above.