added line to changelog for emigration tick persistence change

changelog.txt

@@ -41,6 +41,7 @@ Template for new versions:
 
 ## Misc Improvements
 - `control-panel`: Add realistic-melting tweak to control-panel registry
+- `emigration`: last cycle tick is persisted so that save-and-reload no longer resets the emigration timeout, making gameplay more consistent
 - `idle-crafting`: also support making shell crafts for workshops with linked input stockpiles
 - `gui/gm-editor`: automatic display of semantic values for language_name fields
 - `fix/stuck-worship`: reduced console output by default. Added ``--verbose`` and ``--quiet`` options.