It was probably removed while working on movement counter, as the movement counter uses high pass on the interrupts but not on data.
The original function seems to have been:
lis2dh12_ret_t lis2dh12_set_highpass(uint8_t highpass)
ctrl = highpass;
return lis2dh12_write_register(LIS2DH12_CTRL_REG2, ctrl, 1);
where highpass is the control register 2 value.
You’d probably want to make a function to read the LIS2DH12_CTRL_REG2, set bit 0x08 (FDS) in the read value and write the register value with high pass bit set to the LIS2DH12