65/155: doc: Mention the d3.js backend of 'guix graph'.

[John Darrington]

jmd pushed a commit to branch wip-installer
in repository guix.

commit da05179ba47beaeade58c323fd023be13a3a8ddf
Author: Ludovic Courtès <address@hidden>
Date:   Sun Dec 18 17:11:13 2016 +0100

    doc: Mention the d3.js backend of 'guix graph'.
    
    * doc/guix.texi (Invoking guix graph): Mention the d3.js backend.
---
 doc/guix.texi |   12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

diff --git a/doc/guix.texi b/doc/guix.texi
index 3b2368b..99bde4a 100644
--- a/doc/guix.texi
+++ b/doc/guix.texi
@@ -5726,11 +5726,13 @@ Consider packages for @var{system}---e.g., 
@code{x86_64-linux}.
 Packages and their dependencies form a @dfn{graph}, specifically a
 directed acyclic graph (DAG).  It can quickly become difficult to have a
 mental model of the package DAG, so the @command{guix graph} command
-provides a visual representation of the DAG.  @command{guix graph}
-emits a DAG representation in the input format of
+provides a visual representation of the DAG.  By default,
address@hidden graph} emits a DAG representation in the input format of
 @uref{http://www.graphviz.org/, Graphviz}, so its output can be passed
-directly to the @command{dot} command of Graphviz.  The general
-syntax is:
+directly to the @command{dot} command of Graphviz.  It can also emit an
+HTML page with embedded JavaScript code to display a ``chord diagram''
+in a Web browser, using the @uref{https://d3js.org/, d3.js} library.
+The general syntax is:
 
 @example
 guix graph @var{options} @address@hidden
@@ -5855,6 +5857,8 @@ Produce a graph using the selected @var{backend}.
 @item --list-backends
 List the supported graph backends.
 
+Currently, the available backends are Graphviz and d3.js.
+
 @item address@hidden
 @itemx -e @var{expr}
 Consider the package @var{expr} evaluates to.