Deal with quantifiers appearing on capture's enclosing patterns

- Use a proper enum type for quantifiers.
- Drop quantifiers from `TSQueryStep`, which was not used.
- Keep track of the captures introduced during a pattern parse, and
  apply the quantifier for the pattern to the captures that were
  introduced by the pattern or any sub patterns.
- Use 'quantifier' instead of 'suffix'.

lib/include/tree_sitter/api.h

@@ -106,6 +106,13 @@ typedef struct {
   uint32_t index;
 } TSQueryCapture;
 
+typedef enum {
+  One,
+  OneOrMore,
+  ZeroOrOne,
+  ZeroOrMore,
+} TSQuantifier;
+
 typedef struct {
   uint32_t id;
   uint16_t pattern_index;
@@ -740,7 +747,13 @@ const char *ts_query_capture_name_for_id(
   uint32_t id,
   uint32_t *length
 );
-char ts_query_capture_suffix_for_id(
+
+/**
+ * Get the quantifier of the query's captures, or one of the query's string
+ * literals. Each capture and string is associated with a numeric id based
+ * on the order that it appeared in the query's source.
+ */
+TSQuantifier ts_query_capture_quantifier_for_id(
   const TSQuery *,
   uint32_t id
 );