Implement CLASS NODE locations

The following Location information has been added This is the information required for parse.y to be a universal parser:

```
❯ ruby --parser=prism --dump=parsetree -e "class A < B; end"
@ ProgramNode (location: (1,0)-(1,16))
+-- locals: []
+-- statements:
    @ StatementsNode (location: (1,0)-(1,16))
    +-- body: (length: 1)
        +-- @ ClassNode (location: (1,0)-(1,16))
            +-- locals: []
            +-- class_keyword_loc: (1,0)-(1,5) = "class"
            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
            +-- constant_path:
            |   @ ConstantReadNode (location: (1,6)-(1,7))
            |   +-- name: :A
            +-- inheritance_operator_loc: (1,8)-(1,9) = "<"
            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
            +-- superclass:
            |   @ ConstantReadNode (location: (1,10)-(1,11))
            |   +-- name: :B
            +-- body: nil
            +-- end_keyword_loc: (1,13)-(1,16) = "end"
            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
            +-- name: :A
```

rubyparser.h

@@ -891,6 +891,9 @@ typedef struct RNode_CLASS {
     struct RNode *nd_cpath;
     struct RNode *nd_body;
     struct RNode *nd_super;
+    rb_code_location_t class_keyword_loc;
+    rb_code_location_t inheritance_operator_loc;
+    rb_code_location_t end_keyword_loc;
 } rb_node_class_t;
 
 typedef struct RNode_MODULE {