Fixed `UncheckedArray`

[Patitotective]

Edited imgui.nim:

• ImVector.data: UncheckedArray[T] -> ptr UncheckedArray[T]
• ImDrawList.cmdLists: UncheckedArray[ptr ImDrawList] -> ptr UncheckedArray[ptr ImDrawList]

Usage Example

import nimgl/imgui, nimgl/imgui/[impl_opengl, impl_glfw]
import nimgl/[opengl, glfw]

proc main() =
  doAssert glfwInit()

  glfwWindowHint(GLFWContextVersionMajor, 3)
  glfwWindowHint(GLFWContextVersionMinor, 3)
  glfwWindowHint(GLFWOpenglForwardCompat, GLFW_TRUE)
  glfwWindowHint(GLFWOpenglProfile, GLFW_OPENGL_CORE_PROFILE)
  glfwWindowHint(GLFWResizable, GLFW_FALSE)

  var w: GLFWWindow = glfwCreateWindow(1280, 720)
  if w == nil:
    quit(-1)

  w.makeContextCurrent()

  doAssert glInit()

  let context = igCreateContext()
  #let io = igGetIO()

  doAssert igGlfwInitForOpenGL(w, true)
  doAssert igOpenGL3Init()

  igStyleColorsCherry()

  while not w.windowShouldClose:
    glfwPollEvents()

    igOpenGL3NewFrame()
    igGlfwNewFrame()
    igNewFrame()

    # Simple window
    igBegin("Hello, world!")

    var filter: ImGuiTextFilter # Before it complained Error: invalid type: 'UncheckedArray[ImGuiTextRange]' in this context: 'ImGuiTextFilter' for var
    filter.addr.draw()
    
    for line in ["aaa1.c", "bbb1.c", "ccc1.c", "aaa2.cpp", "bbb2.cpp", "ccc2.cpp", "abc.h", "hello, world"]:
      if filter.addr.passFilter(line):
        igBulletText("%s", line)

    igEnd()
    # End simple window

    igRender()

    glClearColor(0.45f, 0.55f, 0.60f, 1.00f)
    glClear(GL_COLOR_BUFFER_BIT)

    igOpenGL3RenderDrawData(igGetDrawData())

    w.swapBuffers()

  igOpenGL3Shutdown()
  igGlfwShutdown()
  context.igDestroyContext()

  w.destroyWindow()
  glfwTerminate()

main()