Collapse rules that contain only a single token

src/compiler/rules/rule.cpp

@@ -6,6 +6,10 @@ using std::string;
 
 namespace tree_sitter {
     namespace rules {
+        bool Rule::operator!=(const Rule &other) const {
+            return !this->operator==(other);
+        }
+        
         ostream& operator<<(ostream& stream, const Rule &rule) {
             return stream << rule.to_string();
         }

src/compiler/rules/rule.h

@@ -13,6 +13,7 @@ namespace tree_sitter {
         class Rule {
         public:
             virtual bool operator==(const Rule& other) const = 0;
+            bool operator!=(const Rule& other) const;
             virtual size_t hash_code() const = 0;
             virtual rule_ptr copy() const = 0;
             virtual std::string to_string() const = 0;