Update devel/fossil to 2.18

Changes for version 2.18 (2022-02-23)

  *  Added support for [./ssl-server.md|SSL/TLS server mode] for commands
    like "[/help?cmd=server|fossil server]" and "[/help?cmd=http|fossil http]"
  *  The new [/help?cmd=cherry-pick|cherry-pick command] is an alias for
    [/help?cmd=merge|merge --cherrypick].
  *  Add new setting "[/help?cmd=large-file-size|large-file-size]".  If the size
    of any file in a commit exceeds this size, a warning is issued.
  *  Query parameter "year=YYYY" is now accepted by [/help?cmd=/timeline|/timeline].
  *  The [/help?cmd=tar|tar] and [/help?cmd=zip|zip commands] no longer
    sterilize the manifest file.
  *  Futher improvement to diff alignment in cases that involve both
    edits and indentation changes.
  *  [/doc/trunk/www/chat.md|Chat] improvements:<ul>
    <li>  [/help?cmd=/chat|The /chat page] input options have been reworked
          again for better cross-browser portability.
    <li>  When sending a [/help?cmd=/chat|/chat] message fails, it is no longer
          immediately lost and sending may optionally be retried.
    <li>  [/help?cmd=/chat|/chat] can now optionally embed attachments of certain
          types directly into message bodies via an iframe.
    <li>  Add the "--as FILENAME" option to the "[/help?cmd=chat|fossil chat send]"
          command.
    <li>  Added the "[/help?cmd=chat|fossil chat pull]" command, available to
          administrators only, for backing up the chat conversation.
    </ul>
  *  Promote the test-detach command into the [/help?cmd=detach|detach command].
  *  For "[/help?cmd=pull|fossil pull]" with the --from-parent-project option,
    if no URL is specified then use the last URL from the most recent prior
    "fossil pull --from-parent-project".
  *  Add options --project-name and --project-desc to the
    "[/help?cmd=init|fossil init]" command.
  *  The [/help?cmd=/ext|/ext page] generates the SERVER_SOFTWARE environment
    variable for clients.
  *  Fix the REQUEST_URI [/doc/trunk/www/aboutcgi.wiki#cgivar|CGI variable] such
    that it includes the query string.  This is how most other systems understand
    REQUEST_URI.
  *  Added the --transport-command option to [/help?cmd=sync|fossil sync]
    and similar.

(js)