Merge #14214: convert C-style (void) parameter lists to C++ style ()

3ccfa34b32 convert C-style (void) parameter lists to C++ style () (Arvid Norberg)

Pull request description:

  In C, an empty parameter list, `()`, means the function takes any arguments, and `(void)` means the function does not take any parameters.
  In C++, an empty parameter list means the function does not take any parameters.

  So, C++ still supports `(void)` parameter lists with the same semantics, why change to `()`?

  1. removing the redundant `void` improves signal-to-noise ratio of the code
  2. using `(void)` exposes a rare inconsistency in that a template taking a template `(T)` parameter list, cannot be instantiated with `T=void`

Tree-SHA512: be2897b6c5e474873aa878ed6bac098382cd21866aec33752fe40b089a6331aa6263cae749aba1b4a41e8467f1a47086d32eb74abaf09927fd5a2f44a4b2109a

src/httpserver.cpp

@@ -498,7 +498,7 @@ static void httpevent_callback_fn(evutil_socket_t, short, void* data)
         delete self;
 }
 
-HTTPEvent::HTTPEvent(struct event_base* base, bool _deleteWhenTriggered, const std::function<void(void)>& _handler):
+HTTPEvent::HTTPEvent(struct event_base* base, bool _deleteWhenTriggered, const std::function<void()>& _handler):
     deleteWhenTriggered(_deleteWhenTriggered), handler(_handler)
 {
     ev = event_new(base, -1, 0, httpevent_callback_fn, this);