Update changelog.txt for unit-syndromes fix

Author: Pebob

changelog.txt

@@ -57,6 +57,7 @@ Template for new versions:
 - `gui/sandbox`: fix scrollbar moving double distance on click
 - `hide-tutorials`: fix the embark tutorial prompt sometimes not being skipped
 - `full-heal`: fix removal of corpse after resurrection
+- `gui/unit-syndromes`: the syndrome names should now be visible
 
 ## Misc Improvements
 - `prioritize`: refuse to automatically prioritize dig and smooth/carve job types since it can break the DF job scheduler; instead, print a suggestion that the player use specialized units and vanilla designation priorities