Tweak changes file for 25024 to mention "check-typos"

changes/ticket25024

@@ -1,3 +1,4 @@
   o Minor features (code quality):
-    - Add spell checking using misspell in Makefile.
+    - Add optional spell-checking for the Tor codebase, using the "misspell"
+      program.  To use this feature, run "make check-typos".
       Closes ticket 25024.