(BREAKING) Commented out obsolete ImageButton(). (#5533, #4471, #2464, #1390)

imgui.cpp

@@ -438,6 +438,11 @@ CODE
                             - io.PlatformLocaleDecimalPoint -> platform_io.Platform_LocaleDecimalPoint (#7389, #6719, #2278)
                             - access those via GetPlatformIO() instead of GetIO().
                          some were introduced very recently and often automatically setup by core library and backends, so for those we are exceptionally not maintaining a legacy redirection symbol.
+                       - commented the old ImageButton() signature obsoleted in 1.89 (~August 2022). As a reminder:
+                            - old ImageButton() before 1.89 used ImTextureId as item id (created issue with e.g. multiple buttons in same scope, transient texture id values, opaque computation of ID)
+                            - new ImageButton() since 1.89 requires an explicit 'const char* str_id'
+                            - old ImageButton() before 1.89 had frame_padding' override argument.
+                            - new ImageButton() since 1.89 always use style.FramePadding, which you can freely override with PushStyleVar()/PopStyleVar().
  - 2024/07/25 (1.91.0) - obsoleted GetContentRegionMax(), GetWindowContentRegionMin() and GetWindowContentRegionMax(). (see #7838 on GitHub for more info)
                          you should never need those functions. you can do everything with GetCursorScreenPos() and GetContentRegionAvail() in a more simple way.
                             - instead of:  GetWindowContentRegionMax().x - GetCursorPos().x