Columns: undid the change in 1.75 were Columns()/BeginColumns() were preemptively limited to 64 columns with an assert. (#3037, #125)

Essentially reverting 9d444062f9.

docs/CHANGELOG.txt

@@ -64,6 +64,8 @@ Other Changes:
   - sizeof(ImWchar) goes from 2 to 4. IM_UNICODE_CODEPOINT_MAX goes from 0xFFFF to 0x10FFFF.
   - Various structures such as ImFont, ImFontGlyphRangesBuilder will use more memory, this
     is currently not particularly efficient.
+- Columns: undid the change in 1.75 were Columns()/BeginColumns() were preemptively limited
+  to 64 columns with an assert. (#3037, #125)
 - Window: Fixed a bug with child window inheriting ItemFlags from their parent when the child
   window also manipulate the ItemFlags stack. (#3024) [@Stanbroek]
 - Font: Fixed non-ASCII space occasionally creating unnecessary empty polygons.
@@ -121,6 +123,7 @@ Breaking Changes:
 - ImDrawList::AddCircle()/AddCircleFilled() functions don't accept negative radius.
 - Limiting Columns()/BeginColumns() api to 64 columns with an assert. While the current code
   technically supports it, future code may not so we're putting the restriction ahead.
+  [Undid that change in 1.76]
 - imgui_internal.h: changed ImRect() default constructor initializes all fields to 0.0f instead
   of (FLT_MAX,FLT_MAX,-FLT_MAX,-FLT_MAX). If you used ImRect::Add() to create bounding boxes by
   adding points into it without explicit initialization, you may need to fix your initial value.

imgui.cpp

@@ -367,7 +367,7 @@ CODE
  You can read releases logs https://github.com/ocornut/imgui/releases for more details.
 
  - 2020/01/22 (1.75) - ImDrawList::AddCircle()/AddCircleFilled() functions don't accept negative radius any more.
- - 2019/12/17 (1.75) - made Columns() limited to 64 columns by asserting above that limit. While the current code technically supports it, future code may not so we're putting the restriction ahead.
+ - 2019/12/17 (1.75) - [undid this change in 1.76] made Columns() limited to 64 columns by asserting above that limit. While the current code technically supports it, future code may not so we're putting the restriction ahead.
  - 2019/12/13 (1.75) - [imgui_internal.h] changed ImRect() default constructor initializes all fields to 0.0f instead of (FLT_MAX,FLT_MAX,-FLT_MAX,-FLT_MAX). If you used ImRect::Add() to create bounding boxes by adding multiple points into it, you may need to fix your initial value.
  - 2019/12/08 (1.75) - removed redirecting functions/enums that were marked obsolete in 1.53 (December 2017):
                        - ShowTestWindow()                    -> use ShowDemoWindow()

imgui_widgets.cpp

@@ -7498,8 +7498,8 @@ void ImGui::BeginColumns(const char* str_id, int columns_count, ImGuiColumnsFlag
     ImGuiContext& g = *GImGui;
     ImGuiWindow* window = GetCurrentWindow();
 
-    IM_ASSERT(columns_count >= 1 && columns_count <= 64);   // Maximum 64 columns
+    IM_ASSERT(columns_count >= 1);
-    IM_ASSERT(window->DC.CurrentColumns == NULL);           // Nested columns are currently not supported
+    IM_ASSERT(window->DC.CurrentColumns == NULL);   // Nested columns are currently not supported
 
     // Acquire storage for the columns set
     ImGuiID id = GetColumnsID(str_id, columns_count);