(Breaking) Overlap: Renamed 'ImGuiTreeNodeFlags_AllowItemOverlap' to 'ImGuiTreeNodeFlags_AllowOverlap', 'ImGuiSelectableFlags_AllowItemOverlap' to 'ImGuiSelectableFlags_AllowOverlap'. Kept redirecting enums (will obsolete). (#6512, #3909, #517)

+ Internals: Renamed 'ImGuiButtonFlags_AllowItemOverlap' to 'ImGuiButtonFlags_AllowOverlap' without redirection.
7 files changed