igPushStyleColor receives an ImVec4 instead of a ImU32
https://github.com/nimgl/nimgl/blob/991cf5e6c28245ec0144607f500c446aa68f21b3/src/nimgl/imgui.nim#L1608

Proper signature:
```
proc igPushStyleColor*(idx: ImGuiCol, col: ImVec4): void {.imgui_lib, importc: "igPushStyleColor".}
```