emacs: command: Disambiguate "w" key in build options.

This is a followup to commit 47c0f92c37dc7d50d9d4598ce5b91c4cdfec6ed1.

* emacs/guix-command.el (guix-command-improve-common-build-argument):
  Use "W" key for '--with-input' option (leave "w" for '--with-source').

guix system: Rename 'dmd-graph' to 'shepherd-graph'.

* doc/images/dmd-graph.dot: Rename to...
* doc/images/shepherd-graph.dot: ... this.
* doc.am (DOT_FILES): Adjust accordingly.
* guix/scripts/system.scm (dmd-service-node-label)
  (dmd-service-node-type, export-dmd-graph): Rename to...
  (shepherd-service-node-label, shepherd-service-node-type)
  (export-shepherd-graph): ... this.
  (show-help, process-action, process-command): Rename 'dmd-graph' to
  'shepherd-graph'.
* emacs/guix-command.el (guix-command-additional-execute-arguments)
  (guix-command-special-executors): Likewise.
* doc/guix.texi: Likewise.
* doc/emacs.texi (Emacs Popup Interface): Likewise.

Merge branch 'master' into core-updates

emacs: Complete --file in 'guix build' popup.

* emacs/guix-command.el (guix-command-improve-build-argument): Use
  'guix-read-file-name' to complete --file option.

Merge branch 'master' into core-updates

emacs: Use "cl-list*" instead of "apply #'list".

* emacs/guix-command.el (guix-run-view-build-log): Use cl-list*.
  (guix-run-view-size-map): Likewise.
* emacs/guix-external.el (guix-dot-arguments): Likewise.

Merge branch 'master' into core-updates

emacs: Fix '--rounds' option in command popups.

* emacs/guix-command.el (guix-command-improve-common-build-argument):
  Use "R" key for '--rounds' option to avoid conflicts with "r" key in
  'build' popup (--root) and 'package' popup (--remove).

emacs: Add 'guix-build-log-find-file'.

* emacs/guix-build-log.el (guix-build-log-find-file): New procedure.
* emacs/guix-command.el (guix-run-view-build-log): Use it.

emacs: Complete --profile in 'guix package' popup.

* emacs/guix-command.el (guix-command-improve-package-argument): Use
  'guix-read-file-name' to complete --profile option.

emacs: Adjust 'guix environment' popup.

* emacs/guix-command.el (guix-command-improve-environment-argument): Use
  "E" for '--expose' and "S" for '--share' to distinguish them from
  '--expression' and '--system' accordingly.  Make '--ad-hoc' an option
  taking packages instead of a simple switch.
  (guix-command-rest-argument): Complete shell command instead of
  packages for '--' argument.
  (guix-command-additional-arguments): Add fake 'packages' argument.
  New variable.
  (guix-command-additional-arguments): Use it.
  (guix-command-post-process-environment-packages,
  guix-command-post-process-environment-ad-hoc): New functions.
  (guix-command-post-processors): Add "environment" command with the new
  argument processors.

emacs: Adjust 'guix container' popup.

* emacs/guix-command.el (guix-command-improve-action-argument): Use "C"
  key for 'container' action to distinguish it from 'challenge'.
  (guix-command-rest-argument): Add positional arguments.

emacs: Improve post processing of popup arguments.

* emacs/guix-command.el (guix-command-switches,
  guix-command-rest-arg-regexp): New variables.
  (guix-command-post-processors,
  guix-command-post-process-matching-args,
  guix-command-post-process-rest-single,
  guix-command-post-process-rest-multiple,
  guix-command-post-process-rest-multiple-leave,
  guix-command-post-process-package-args): New functions.
  (guix-command-post-process-rest-multiple): Take 2 arguments.
  (guix-command-define-popup-action): Adjust accordingly.
* emacs/guix-utils.el (guix-modify): New function.

emacs: Add completions for '--type' option of 'refresh' popup.

* guix/scripts/refresh.scm: Export '%updaters'.
* emacs/guix-main.scm (refresh-updater-names): New procedure.
* emacs/guix-base.el (guix-refresh-updater-names): New function.
* emacs/guix-read.el (guix-read-refresh-updater-names,
  guix-read-refresh-updater-names-string): New functions.
* emacs/guix-command.el (guix-command-improve-refresh-argument): Use
  'guix-read-refresh-updater-names-string'.

Merge branch 'master' into dbus-update

emacs: Add "Packages" option for 'guix challenge' popup.

* emacs/guix-command.el (guix-command-rest-argument): Add "challenge".

Merge branch 'master' into dbus-update

emacs: Add "View graph" actions to system graph commands.

* emacs/guix-command.el (guix-command-additional-execute-arguments,
  guix-command-special-executors): Add "View graph" actions for
  'dmd-graph' and 'extension-graph' commands.

emacs: Disambiguate "d" key in 'system' popup.

* emacs/guix-command.el (guix-command-improve-system-argument): Use "D"
  key for 'disk-image' action (leave "d" for 'dmd-graph').

Merge branch 'master' into core-updates