Refactor Mongoose documentation

PUBLISHED_FROM=e9a4e5c7b4a1d03b93a2a79e29de19e60e919929

docs/c-api/http_server.h/mg_printf_http_chunk.md

@@ -0,0 +1,11 @@
+---
+title: "mg_printf_http_chunk()"
+decl_name: "mg_printf_http_chunk"
+symbol_kind: "func"
+signature: |
+  void mg_printf_http_chunk(struct mg_connection *nc, const char *fmt, ...);
+---
+
+Sends a printf-formatted HTTP chunk.
+Functionality is similar to `mg_send_http_chunk()`. 
+