[Indic] Don't give up syllable parsing upon junk

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

@@ -74,13 +74,13 @@ action next_syllable {
 consonant_syllable =	(c.N? (H.z?|z.H))* c.N? A? (H.z? | matra_group*)? syllable_tail %(found_consonant_syllable);
 vowel_syllable =	(Ra H)? V N? (z?.H.c | ZWJ.c)? matra_group* syllable_tail %(found_vowel_syllable);
 standalone_cluster =	(Ra H)? NBSP N? (z? H c)? matra_group* syllable_tail %(found_standalone_cluster);
-non_indic = X %(found_non_indic);
+other = /./ %(found_non_indic);
 
 syllable =
 	  consonant_syllable
 	| vowel_syllable
 	| standalone_cluster
-	| non_indic
+	| other
 	;
 
 main := (syllable %(next_syllable))**;