Release process: skip step if it's not needed

wiki/src/contribute/APT_repository/custom.mdwn

@@ -381,10 +381,10 @@ In any case:
 
 * [[merge `stable` or `testing` into
   `devel`|APT_repository/custom#workflow-merge-main-branch]]
-* increment the version number in `devel`'s `debian/changelog` to match
+* check if the version number of the last entry in `devel`'s `debian/changelog` matches
   the next major release, so that
   next builds from the `devel` branch do not use the APT suite meant
-  for the last release:
+  for the last release; if this is not the case yet, run:
 
         cd "${RELEASE_CHECKOUT}" && \
         git checkout devel && \