Added arduino-nano to BOARD_INSUFFICIENT_MEMORY/BOARD_BLACKLIST following suit
of how arduino-uno is marked, as arduino-nano is mostly an Uno in a different
form factor.
`UINT16_MAX` should be the same value on all platforms, so why not use
`puts` instead of `printf` here instead. Also, `llvm` detects an issue
with using the `UINT16_MAX` macro with `PRIu16` here.