Fix mongoose docs generation

PUBLISHED_FROM=331821dcd1f7dc8a94581cd8a9b51aa00a89fddc

docs/c-api/mg_util.h/intro.md

@@ -0,0 +1,29 @@
+---
+title: "Utility API"
+symbol_kind: "intro"
+decl_name: "mg_util.h"
+items:
+  - { name: mg_base64_decode.md }
+  - { name: mg_base64_encode.md }
+  - { name: mg_basic_auth_header.md }
+  - { name: mg_conn_addr_to_str.md }
+  - { name: mg_fopen.md }
+  - { name: mg_fread.md }
+  - { name: mg_fwrite.md }
+  - { name: mg_hexdump.md }
+  - { name: mg_hexdump_connection.md }
+  - { name: mg_hexdumpf.md }
+  - { name: mg_is_big_endian.md }
+  - { name: mg_mbuf_append_base64.md }
+  - { name: mg_mbuf_append_base64_putc.md }
+  - { name: mg_open.md }
+  - { name: mg_skip.md }
+  - { name: mg_sock_addr_to_str.md }
+  - { name: mg_sock_to_str.md }
+  - { name: mg_start_thread.md }
+  - { name: mg_stat.md }
+  - { name: mg_url_encode.md }
+---
+
+
+