Move example grammars from fixtures -> examples dir

spec/fixtures/grammars/json.cpp

@@ -1,53 +0,0 @@
-#include "test_grammars.h"
-#include "tree_sitter/compiler.h"
-
-using namespace tree_sitter;
-using namespace rules;
-
-static rule_ptr comma_sep(const rule_ptr &rule) {
-    return choice({
-        seq({
-            rule,
-            repeat(seq({ aux_sym("comma"), rule })),
-        }),
-        blank(),
-    });
-}
-
-namespace test_grammars {
-    Grammar json() {
-        return Grammar("value", {
-            { "value", choice({
-                sym("object"),
-                sym("array"),
-                sym("string"), 
-                sym("number") }) },
-            { "object", seq({
-                aux_sym("left_brace"),
-                comma_sep(seq({
-                    sym("string"),
-                    aux_sym("colon"),
-                    sym("value") })),
-                aux_sym("right_brace"), }) },
-            { "array", seq({
-                aux_sym("left_bracket"),
-                comma_sep(sym("value")),
-                aux_sym("right_bracket"), }) },
-            { "string", seq({
-                character({ '"' }),
-                repeat(choice({
-                    pattern("[^\"]"),
-                    str("\\\""),
-                })),
-                character({ '"' }) }) },
-            { "number", pattern("\\d+") }
-        }, {
-            { "comma", str(",") },
-            { "colon", str(":") },
-            { "left_bracket", str("[") },
-            { "right_bracket", str("]") },
-            { "left_brace", str("{") },
-            { "right_brace", str("}") },
-        });
-    }
-}