Autocomplete should not insert parenthesis for function pointers

[IntegratedQuantum]

Current behavior

It's easy to miss the fact that zls inserted some extra parenthesis there, and the error message of the compiler can also be pretty obscure. Overall it's really annoying to deal with.

Obscure error from the above example

compiler/zig/lib/std/Thread.zig:1050:30: error: unable to evaluate comptime expression
        return tls_thread_id orelse {
               ~~~~~~~~~~~~~~^~~~~~
compiler/zig/lib/std/Thread.zig:589:52: note: called from here
                return LinuxThreadImpl.getCurrentId();
                       ~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~
compiler/zig/lib/std/Thread.zig:277:29: note: called from here
    return Impl.getCurrentId();
           ~~~~~~~~~~~~~~~~~^~
compiler/zig/lib/std/Thread/Mutex.zig:80:47: note: called from here
        const current_id = Thread.getCurrentId();
                           ~~~~~~~~~~~~~~~~~~~^~
compiler/zig/lib/std/Thread/Mutex.zig:44:19: note: called from here
    self.impl.lock();
    ~~~~~~~~~~~~~~^~
src/game.zig:112:13: note: called from here
  mutex.lock();
  ~~~~~~~~~~^~
src/main.zig:593:50: note: called from here
 currentPoint.pos = game.Player.getEyePosBlocking();
                    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~
src/main.zig:364:74: note: called from here
  .{.name = "pos", .key = c.GLFW_KEY_F9, .releaseAction = &storePosAndVel()},
                                                           ~~~~~~~~~~~~~~^~

Proposed improvement

Ideally the result type should be detected, but I think that goes beyond zls's capabilities. Instead it could check if there is an ampersand in front of the function name, if there is then don't add the extra parenthesis.