Release process: drop "untested" indication.

Works for me.

wiki/src/contribute/release_process.mdwn

@@ -802,7 +802,7 @@ Prepare upgrade-description files
      or RC), add `--channel alpha`
    * If preparing anything but a final release (e.g. an alpha, beta
      or RC), drop all `--next-version`
-     arguments, and instead pass (**untested!**)
+     arguments, and instead pass
      `--next-version $(echo ${VERSION:?} | sed -e 's,~rc.*$,,')`
    * Adjust `--next-version "${VERSION:?}.1"` so it matches the next
      potential emergency release. E.g. when releasing 3.7.1,