Fix infinite loop in ImFontGlyphRangesBuilder::AddRanges if the user passes upper range = UINT16_MAX without IMGUI_USE_WCHAR32. (#4802)

docs/CHANGELOG.txt

@@ -88,6 +88,8 @@ Other Changes:
 - Clipper: fixed invalid state when number of frozen table row is smaller than ItemCount.
 - Drag and Drop: BeginDragDropSource() with ImGuiDragDropFlags_SourceAllowNullID doesn't lose
   tooltip when scrolling. (#143)
+- Fonts: fixed infinite loop in ImFontGlyphRangesBuilder::AddRanges() when passing UINT16_MAX without
+  the IMGUI_USE_WCHAR32 compile-time option. (#4802) [@SlavicPotato]
 - Metrics: Added a node showing windows in submission order and showing the Begin() stack.
 - Misc: Added missing ImGuiMouseCursor_NotAllowed cursor for software rendering (when the
   io.MouseDrawCursor flag is enabled). (#4713) [@nobody-special666]

imgui_draw.cpp

@@ -3080,8 +3080,8 @@ void ImFontGlyphRangesBuilder::AddText(const char* text, const char* text_end)
 void ImFontGlyphRangesBuilder::AddRanges(const ImWchar* ranges)
 {
     for (; ranges[0]; ranges += 2)
-        for (ImWchar c = ranges[0]; c <= ranges[1]; c++)
-            AddChar(c);
+        for (unsigned int c = ranges[0]; c <= ranges[1] && c <= IM_UNICODE_CODEPOINT_MAX; c++)
+            AddChar((ImWchar)c);
 }
 
 void ImFontGlyphRangesBuilder::BuildRanges(ImVector<ImWchar>* out_ranges)