Merge topic branch t/ff-compat into master

A single commit which removes support for the old syntax of the ff
command where negative values could be specified with a postfix such
as "ff 30-". This syntax has long been deprecated.

* refs/heads/t/ff-compat:
  server: Remove compatibility code of com_ff().

diff --cc NEWS.md
index fff7a242bba99d3a322b47c0d101d36b93e8d8d5,5a00175c3255702b03ec86e0af1938863f53ba4d..92a63ee76b5d86cda54166138731cf3f1423df07
--- 1/NEWS.md
--- 2/NEWS.md
+++ b/NEWS.md
@@@ -1,23 -1,6 +1,25 @@@
  NEWS
  ====
  
 +------------------------------------------
 +0.7.2 (to be announced) "optical friction"
 +------------------------------------------
 +
 +- A major cleanup of the audio file selector.
 +- The client no longer prints error messages from afs commands to
 +  stdout but to stderr.
 +- The sleep subcommand of para_mixer gained two options to control
 +  the startup mood and the time period before fade-out starts. A bunch
 +  of further improvements for this subcommand went in as well.
 +- Minor cleanup of the net subsystem.
 +- The openssl specific code now employs the EVP API to compute hashes.
 +  It should compile without warnings against openssl-3.
++- The deprecated syntax for specifying negative offsets in the argument
++  to the "ff" server command has been removed.
 +
 +Downloads:
 +[tarball](./releases/paraslash-git.tar.xz)
 +
  --------------------------------------
  0.7.1 (2022-10-03) "digital spindrift"
  --------------------------------------

diff --cc command.c
Simple merge