Fix mongoose docs generation

PUBLISHED_FROM=331821dcd1f7dc8a94581cd8a9b51aa00a89fddc

docs/c-api/mg_net.h/struct_mg_mgr.md

@@ -0,0 +1,22 @@
+---
+title: "struct mg_mgr"
+decl_name: "struct mg_mgr"
+symbol_kind: "struct"
+signature: |
+  struct mg_mgr {
+    struct mg_connection *active_connections;
+  #if MG_ENABLE_HEXDUMP
+    const char *hexdump_file; /* Debug hexdump file path */
+  #endif
+  #if MG_ENABLE_BROADCAST
+    sock_t ctl[2]; /* Socketpair for mg_broadcast() */
+  #endif
+    void *user_data; /* User data */
+    int num_ifaces;
+    struct mg_iface **ifaces; /* network interfaces */
+    const char *nameserver;   /* DNS server to use */
+  };
+---
+
+Mongoose event manager. 
+