remove option_phoneme_variants that is never set and always evaluates true

src/libespeak-ng/dictionary.c

 
 	first = true;
 	for (mnem = ph->mnemonic; (c = mnem & 0xff) != 0; mnem = mnem >> 8) {
-		if ((c == '/') && (option_phoneme_variants == 0))
+		if (c == '/') // NOTE: this line used to be (c == '/') && (option_phoneme_variants == 0)) but always evaluated true
 			break; // discard phoneme variant indicator
 
 		if (use_ipa) {

src/libespeak-ng/translate.c

 static int option_emphasis = 0; // 0=normal, 1=normal, 2=weak, 3=moderate, 4=strong
 int option_ssml = 0;
 int option_phoneme_input = 0; // allow [[phonemes]] in input
-int option_phoneme_variants = 0; // 0= don't display phoneme variant mnemonics
 int option_wordgap = 0;
 
 static int count_sayas_digits;

src/libespeak-ng/translate.h

 extern int option_endpause;
 extern int option_ssml;
 extern int option_phoneme_input;   // allow [[phonemes]] in input text
-extern int option_phoneme_variants;
 extern int option_sayas;
 extern int option_wordgap;