[khmer] Remove unused symbol clusters

src/hb-ot-shape-complex-khmer-machine.rl

@@ -53,14 +53,12 @@ DOTTEDCIRCLE = 12;
 RS    = 13;
 Coeng = 14;
 Ra    = 16;
-Symbol= 18;
 
 c = (C | Ra);			# is_consonant
 n = ((ZWNJ?.RS)? (N.N?)?);	# is_consonant_modifier
 z = ZWJ|ZWNJ;			# is_joiner
 
 cn = c.ZWJ?.n?;
-symbol = Symbol.N?;
 matra_group = z{0,3}.M.N?.Coeng?;
 syllable_tail = (z?.SM.SM?.ZWNJ?)? A{0,3}? VD{0,2};
 halant_group = (z?.Coeng.(ZWJ.N?)?);
@@ -71,7 +69,6 @@ halant_or_matra_group = (final_halant_group | (Coeng.ZWJ)? matra_group{0,4}) (Co
 consonant_syllable =	(cn.halant_group){0,4} cn halant_or_matra_group syllable_tail;
 vowel_syllable =	V.n? (ZWJ | (halant_group.cn){0,4} halant_or_matra_group syllable_tail);
 standalone_cluster =	(PLACEHOLDER | DOTTEDCIRCLE).n? (halant_group.cn){0,4} halant_or_matra_group syllable_tail;
-symbol_cluster = 	symbol syllable_tail;
 broken_cluster =	n? (halant_group.cn){0,4} halant_or_matra_group syllable_tail;
 other =			any;
 
@@ -79,7 +76,6 @@ main := |*
 	consonant_syllable	=> { found_syllable (consonant_syllable); };
 	vowel_syllable		=> { found_syllable (vowel_syllable); };
 	standalone_cluster	=> { found_syllable (standalone_cluster); };
-	symbol_cluster		=> { found_syllable (symbol_cluster); };
 	broken_cluster		=> { found_syllable (broken_cluster); };
 	other			=> { found_syllable (non_khmer_cluster); };
 *|;