Fix mongoose docs generation

PUBLISHED_FROM=331821dcd1f7dc8a94581cd8a9b51aa00a89fddc

docs/c-api/mbuf.h/struct_mbuf.md

@@ -0,0 +1,14 @@
+---
+title: "struct mbuf"
+decl_name: "struct mbuf"
+symbol_kind: "struct"
+signature: |
+  struct mbuf {
+    char *buf;   /* Buffer pointer */
+    size_t len;  /* Data length. Data is located between offset 0 and len. */
+    size_t size; /* Buffer size allocated by realloc(1). Must be >= len */
+  };
+---
+
+Memory buffer descriptor 
+