[use] Add a catch-all clause to the machine

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

@@ -129,6 +129,7 @@ number_joiner_terminated_cluster = N VS? (HN N VS?)* HN;
 numeral_cluster = N VS? (HN N VS?)*;
 symbol_cluster = S VS? SMAbv* SMBlw*;
 independent_cluster = (IND | O | Rsv | WJ) VS?;
+other = any;
 
 main := |*
 	independent_cluster			=> { found_syllable (independent_cluster); };
@@ -139,6 +140,7 @@ main := |*
 	numeral_cluster				=> { found_syllable (numeral_cluster); };
 	symbol_cluster				=> { found_syllable (symbol_cluster); };
 	broken_cluster				=> { found_syllable (broken_cluster); };
+	other					=> { found_syllable (non_cluster); };
 *|;
 
 

src/hb-ot-shape-complex-use.cc

@@ -236,6 +236,7 @@ enum syllable_type_t {
   numeral_cluster,
   symbol_cluster,
   broken_cluster,
+  non_cluster,
 };
 
 #include "hb-ot-shape-complex-use-machine.hh"
@@ -315,6 +316,7 @@ setup_topographical_masks (const hb_ot_shape_plan_t *plan,
     {
       case independent_cluster:
       case symbol_cluster:
+      case non_cluster:
 	/* These don't join.  Nothing to do. */
 	last_form = _NONE;
 	break;