emacs: Add 'guix-graph-type-names'.

* emacs/guix-main.scm: Use (guix scripts graph) module.
  (graph-type-names): New procedure.
* emacs/guix-base.el (guix-graph-type-names): New function.

guix graph: Export node types and <node-type> accessors.

* guix/scripts/graph.scm (%node-types, node-type, node-type?,
  node-type-identifier, node-type-label, node-type-edges,
  node-type-convert, node-type-name, node-type-description): Export.

emacs: Add 'guix-lint-checker-names'.

* emacs/guix-main.scm: Use (guix scripts lint) module.
  (lint-checker-names): New procedure.
* emacs/guix-base.el (guix-lint-checker-names): New function.

guix lint: Export checkers and <lint-checker> accessors.

* guix/scripts/lint.scm (%checkers, lint-checker, lint-checker?,
  lint-checker-name, lint-checker-description, lint-checker-check):
  Export.

emacs: Add 'guix-memoized-defalias' macro.

* emacs/guix-utils.el (guix-memoized-defalias): New macro.
  (guix-memoized-font-lock-keywords): New variable.

emacs: Add 'guix-any'.

* emacs/guix-utils.el (guix-any): New function.

emacs: Add utils to copy guix command.

* emacs/guix-utils.el (guix-copy-as-kill, guix-copy-command-as-kill):
  New functions.

emacs: Add utils to make symbol and string for guix command.

* emacs/guix-utils.el (guix-shell-quote-argument, guix-command-symbol,
  guix-command-string): New functions.

emacs: Add and use 'guix-concat-strings'.

* emacs/guix-utils.el (guix-concat-strings): New function.
* emacs/guix-pcomplete.el (guix-pcomplete-short-options): Use it.
* emacs/guix-base.el (guix-get-package-strings): Likewise.

emacs: Add and use 'guix-while-search'.

* emacs/guix-utils.el (guix-while-search): New macro.
* emacs/guix-pcomplete.el (guix-pcomplete-run-guix-and-search): Use it.
* emacs/guix-prettify.el (guix-prettify-decompose-buffer): Likewise.

emacs: Add 'guix-prettify' to 'guix' custom group.

* emacs/guix-prettify.el (guix-prettify): Add 'guix' group.

emacs: Remove leftover internal variable.

This is a followup to commit 74cc67372ec3771b157c015da4ba7ed5d921799f.

* emacs/guix-base.el (guix-define-buffer-type): Remove 'mode-map'
  variable.

gnu: clutter: Add "doc" output.

* gnu/packages/gnome.scm (clutter)[outputs]: New field.
  [arguments]: Pass --with-html-dir.

gnu: Add libchamplain.

* gnu/packages/gnome.scm (libchamplain): New variable.

gnu: Make ruby-diff-lcs a public package.

* gnu/packages/ruby.scm (ruby-diff-lcs-for-rspec): Rename this...
  (ruby-diff-lcs): ... to this, and export it.
  (ruby-rspec-expectation, ruby-rspec-mocks): Use new varaible.

download: Keep a single copy of the mirror file.

This saves ~10% on 'guix build inkscape -Sd'.

* guix/download.scm (%mirror-file): New variable.
  (url-fetch): Remove #:mirrors parameter.
  Remove 'mirror-file'; refer to '%mirror-file' instead.

doc: Mention the "normalized codeset" used in locale names.

* doc/guix.texi (Locales): Introduce "codeset".
  <%default-locale-definitions>: Mention the "normalized codeset", with
  an xref to libc's manual.
* gnu/system/locale.scm (%default-locale-definitions)[utf8-locale]:
  Mention the "normalized codeset" in a comment.

refresh: Add missing newline in warning message.

Reported by karhunkynsi on #guix.

* guix/scripts/refresh.scm (update-package): Add missing newline in
  string literal passed to 'warning'.

gnu: ruby-i18n: Update to 0.7.0.

* gnu/packages/ruby.scm (ruby-i18n): Update to 0.7.0.

gnu: mpv: Replace "jack-2" with "jack-1".

* gnu/packages/video.scm (mpv)[inputs]: Replace "jack-2" with "jack-1".