Fix comment for mg_event_handler_t

PUBLISHED_FROM=cd50a664039b4a74cb7d4d08990f415912585f7d

docs/c-api/net.h/items.json

@@ -88,6 +88,10 @@
             "type": "markdown",
             "name": "mg_time.md"
         },
+        {
+            "type": "markdown",
+            "name": "mg_event_handler_t.md"
+        },
         {
             "type": "markdown",
             "name": "struct_mg_str.md"

docs/c-api/net.h/mg_event_handler_t.md

+---
+title: "mg_event_handler_t"
+decl_name: "mg_event_handler_t"
+symbol_kind: "typedef"
+signature: |
+  typedef void (*mg_event_handler_t)(struct mg_connection *, int ev, void *);
+---
+
+Callback function (event handler) prototype, must be defined by user.
+Mongoose calls event handler, passing events defined below. 
+