Docs are generated for Mongoose

Comments in headers are changed a bit: removed adoc-specific stuff,
markdown is used instead

PUBLISHED_FROM=9242cce85cc52a47a197d377e7e23804721a6bb5

docs/c-api/http.h/mg_printf_html_escape.md

@@ -0,0 +1,10 @@
+---
+title: "mg_printf_html_escape()"
+decl_name: "mg_printf_html_escape"
+symbol_kind: "func"
+signature: |
+  void mg_printf_html_escape(struct mg_connection *nc, const char *fmt, ...);
+---
+
+Send printf-formatted HTTP chunk, escaping HTML tags. 
+