doc: Recommend using the installer script.

* doc/guix.texi (Installation): Make it clear that the installer script is the
recommended, easy way to install Guix.

doc/guix.texi

@@ -25,7 +25,7 @@ Copyright @copyright{} 2015, 2016 Mathieu Lirzin@*
 Copyright @copyright{} 2014 Pierre-Antoine Rault@*
 Copyright @copyright{} 2015 Taylan Ulrich Bayırlı/Kammer@*
 Copyright @copyright{} 2015, 2016, 2017 Leo Famulari@*
-Copyright @copyright{} 2015, 2016, 2017, 2018 Ricardo Wurmus@*
+Copyright @copyright{} 2015, 2016, 2017, 2018, 2019 Ricardo Wurmus@*
 Copyright @copyright{} 2016 Ben Woodcroft@*
 Copyright @copyright{} 2016, 2017, 2018 Chris Marusich@*
 Copyright @copyright{} 2016, 2017, 2018 Efraim Flashner@*
@@ -394,29 +394,34 @@ garbage collection of packages (@pxref{Features}).
 @chapter Installation
 
 @cindex installing Guix
-@cindex official website
-GNU Guix is available for download from its website at
-@url{http://www.gnu.org/software/guix/}.  This section describes the
-software requirements of Guix, as well as how to install it and get
-ready to use it.
 
-Note that this section is concerned with the installation of the package
-manager, which can be done on top of a running GNU/Linux system.  If,
-instead, you want to install the complete GNU operating system,
-@pxref{System Installation}.
+@quotation Note
+We recommend the use of this
+@uref{https://git.savannah.gnu.org/cgit/guix.git/plain/etc/guix-install.sh,
+shell installer script} to install Guix on top of a running GNU/Linux system,
+thereafter called a @dfn{foreign distro}.@footnote{This section is concerned
+with the installation of the package manager, which can be done on top of a
+running GNU/Linux system.  If, instead, you want to install the complete GNU
+operating system, @pxref{System Installation}.} The script automates the
+download, installation, and initial configuration of Guix.  It should be run
+as the root user.
+@end quotation
 
 @cindex foreign distro
 @cindex directories related to foreign distro
-
-When installed on a running GNU/Linux system---thereafter called a
-@dfn{foreign distro}---GNU@tie{}Guix complements the available tools
-without interference.  Its data lives exclusively in two directories,
-usually @file{/gnu/store} and @file{/var/guix}; other files on your
-system, such as @file{/etc}, are left untouched.
+When installed on a foreign distro, GNU@tie{}Guix complements the available
+tools without interference.  Its data lives exclusively in two directories,
+usually @file{/gnu/store} and @file{/var/guix}; other files on your system,
+such as @file{/etc}, are left untouched.
 
 Once installed, Guix can be updated by running @command{guix pull}
 (@pxref{Invoking guix pull}).
 
+If you prefer to perform the installation steps manually or want to tweak
+them, you may find the following subsections useful.  They describe the
+software requirements of Guix, as well as how to install it manually and get
+ready to use it.
+
 @menu
 * Binary Installation::         Getting Guix running in no time!
 * Requirements::                Software needed to build and run Guix.
@@ -437,11 +442,6 @@ dependencies.  This is often quicker than installing from source, which
 is described in the next sections.  The only requirement is to have
 GNU@tie{}tar and Xz.
 
-We provide a
-@uref{https://git.savannah.gnu.org/cgit/guix.git/plain/etc/guix-install.sh,
-shell installer script}, which automates the download, installation, and
-initial configuration of Guix.  It should be run as the root user.
-
 Installing goes along these lines:
 
 @enumerate
@@ -638,6 +638,10 @@ build procedure for Guix is the same as for other GNU software, and is
 not covered here.  Please see the files @file{README} and @file{INSTALL}
 in the Guix source tree for additional details.
 
+@cindex official website
+GNU Guix is available for download from its website at
+@url{https://www.gnu.org/software/guix/}.
+
 GNU Guix depends on the following packages:
 
 @itemize