Fonts: amend/comment on FontDataOwnedByAtlas=false fix being a breaking change. (#9086, #8465)

docs/CHANGELOG.txt

@@ -41,14 +41,21 @@ HOW TO UPDATE?
 
 Breaking Changes:
 
+- Fonts: Fixed handling of `ImFontConfig::FontDataOwnedByAtlas = false` which
+  did erroneously make a copy of the font data, essentially defeating the purpose
+  of this flag and wasting memory (undetected since July 2015 and now spotted
+  by @TellowKrinkle, this is perhaps the oldest bug in Dear ImGui history,
+  albeit for a rarely used feature!) (#9086, #8465)
+  HOWEVER, fixing this bug is likely to surface bugs in user/app code:
+  - Prior to 1.92, font data only needs to be available during the atlas->AddFontXXX() call.
+  - Since 1.92, font data needs to available until atlas->RemoveFont(), or more typically
+    until a shutdown of the owning context or font atlas.
+  - The fact that handling of `FontDataOwnedByAtlas = false` was broken
+    bypassed the issue altogether.
+
 Other Changes:
 
 - Fonts:
-  - Fixed handling of `ImFontConfig::FontDataOwnedByAtlas = false` which
-    did erroneously make a copy of the font data, essentially defeating the purpose
-    of this flag and wasting memory.
-    Undetected since July 2015 and now spotted by @TellowKrinkle, this is perhaps
-    the oldest bug in Dear ImGui history (albeit for a rarely used feature)! (#9086)
   - Fixed an issue related to EllipsisChar handling, while changing
     font loader or font loader flags dynamically in Style->Fonts menus.
 - Textures: