changelog: Add note about entrypoint changes

CHANGELOG.md

@@ -3,6 +3,7 @@
  - coreinit's `exit` is no longer defined in `<coreinit/exit.h>`. Please use `<stdlib.h>` instead, which pulls in newlib's exit.
  - RPL import sections (`.fimport_coreinit` etc.) are now garbage-collected when using wut-tools 1.1.0 or above (required). Code relying on weak links to Cafe functions may exhibit different behaviour.
  - Changes to CMake's linker flags may cause existing build trees to fail. Please delete any old build files and re-run CMake.
+ - Two new symbols, `__rpx_start` and `__rpl_start`, are now used internally by the toolchain, while `_start` is now undefined. As usual, applications are strongly discouraged from prefixing any symbol with two underscores, in order to avoid conflicts of this type.
 
 ###### Deprecations
  - `WUT_ROOT` should no longer be defined in the user's environment, and will be set to `$DEVKITPRO/wut` internally. CMake lists and makefiles that use `$WUT_ROOT/share` to find `wut.mk` or `wut.toolchain.cmake` should be changed to `$DEVKITPRO/wut/share`.
@@ -14,6 +15,7 @@
  - Builds refactored: wut now uses Makefiles to build itself, as well as providing a devkitPro-style `wut_rules` file - see the `samples/make` folder. The cmake samples are now in `samples/cmake`.
  - A new linking feature, `__rplwrap`, was added to help deal with conflicts between newlib's and Cafe's functions. Because of this, wut 1.0.0-beta9 requires wut-tools 1.1.0 or newer.
  - Using rplwrap, newlib's `exit` is now correctly chained with coreinit's - calls like `atexit` should work; whether calling `exit` or just returning from `main`. Applications using coreinit's `_Exit` are encouraged to migrate to a normal `exit` call.
+ - A new header file, `<coreinit/codegen.h>`, has been added and documented for OSCodegen functionality.
 
 
 #### wut 1.0.0-beta8