code cleanup: remove unused stress_amps_r

It is set but never used.

src/libespeak-ng/tr_languages.c

 
 	for (ix = 0; ix < 8; ix++) {
 		tr->stress_amps[ix] = stress_amps2[ix];
-		tr->stress_amps_r[ix] = stress_amps2[ix] - 1;
 		tr->stress_lengths[ix] = stress_lengths2[ix];
 	}
 	memset(&(tr->langopts), 0, sizeof(tr->langopts));

src/libespeak-ng/translate.h

 	int phoneme_tab_ix;
 
 	unsigned char stress_amps[8];
-	unsigned char stress_amps_r[8];
 	short stress_lengths[8];
 	int dict_condition;    // conditional apply some pronunciation rules and dict.lookups
 	int dict_min_size;

src/libespeak-ng/voices.c

 		translator->stress_lengths[ix] += stress_add[ix];
 	for (ix = 0; ix < stress_amps_set; ix++) {
 		translator->stress_amps[ix] = stress_amps[ix];
-		translator->stress_amps_r[ix] = stress_amps[ix] -1;
 	}
 
 	return voice;