Implement REGX 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 '/foo/'
@ ProgramNode (location: (1,0)-(1,5))
+-- locals: []
+-- statements:
    @ StatementsNode (location: (1,0)-(1,5))
    +-- body: (length: 1)
        +-- @ RegularExpressionNode (location: (1,0)-(1,5))
            +-- RegularExpressionFlags: forced_us_ascii_encoding
            +-- opening_loc: (1,0)-(1,1) = "/"
            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
            +-- content_loc: (1,1)-(1,4) = "foo"
            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
            +-- closing_loc: (1,4)-(1,5) = "/"
            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
            +-- unescaped: "foo"
```

1 files changed, 3 insertions, 0 deletions

diff --git a/rubyparser.h b/rubyparser.h
index cd1e88ff6c..2db250c27e 100644
--- a/rubyparser.h
+++ b/rubyparser.h
@@ -737,6 +737,9 @@ typedef struct RNode_REGX {     /* also RNode_MATCH */
 
     struct rb_parser_string *string;
     int options;
+    rb_code_location_t opening_loc;
+    rb_code_location_t content_loc;
+    rb_code_location_t closing_loc;
 } rb_node_regx_t, rb_node_match_t;
 
 typedef rb_node_dstr_t rb_node_dregx_t;