I wanted to use the idiom
```c
#if GUARD
if (condition) {
alternate code
} else
#else
{
common default code
}
```
idiom, in which the common default code is conditioned both on a
compile-time check and a run-time check. However, I got it wrong
and uncrustify chipped in, adding extra brackets around a following
piece of code and re-indenting it.
- Based on espressif/nimble's blecent example code. Confirms that the characteristic is not empty before trying to catalogue its descriptors.
- Running ble_gattc_disc_all_dscs on empty (no length) characteristics fails with the (not-very-informative) BLE_HS_EINVAL error if this check is not performed.
Format:
CIRCUITPY_BLE_NAME = My BLE Board
- the length is limited to 31 characters
- for the NRF version it repeatedly truncates the name if it's too long
- the ESP version defaults to "nimble" if the name is too long
This lets the BLE stack run through the wait period after a VM run
when it may be waiting for more writes due to an auto-reload.
User BLE functionality will have their events stopped. Scanning and
advertising is also stopped.
