Fix typo (#8382)

imgui.h

@@ -3132,7 +3132,7 @@ struct ImDrawList
 
     // General polygon
     // - Only simple polygons are supported by filling functions (no self-intersections, no holes).
-    // - Concave polygon fill is more expensive than convex one: it has O(N^2) complexity. Provided as a convenience fo user but not used by main library.
+    // - Concave polygon fill is more expensive than convex one: it has O(N^2) complexity. Provided as a convenience for the user but not used by the main library.
     IMGUI_API void  AddPolyline(const ImVec2* points, int num_points, ImU32 col, ImDrawFlags flags, float thickness);
     IMGUI_API void  AddConvexPolyFilled(const ImVec2* points, int num_points, ImU32 col);
     IMGUI_API void  AddConcavePolyFilled(const ImVec2* points, int num_points, ImU32 col);