doc: Use HTTPS for external links.

* doc/contributing.texi
  (14.1 Building from Git,
   14.3 The Perfect Setup,
   14.4.1 Software Freedom,
   14.4.4 Synopses and Descriptions,
   14.5.4 Formatting Code):
   Use HTTPS for @uref{}s and @url{}s that support it.

* doc/fdl-1.3.texi
  (Appendix A GNU Free Documentation License):
  Use HTTPS for @uref{}s and @url{}s that support it.

* doc/guix.texi
  (6.3 Build Systems,
   8.8.4 Networking Services,
   8.8.8 Sound Services,
   8.8.16 Web Services,
   8.11 Name Service Switch,
   12.2 Preparing to Use the Bootstrap Binaries);
   Use HTTPS for @uref{}s and @url{}s that support it.

Signed-off-by: Marius Bakke <mbakke@fastmail.com>

1 files changed, 2 insertions, 2 deletions

diff --git a/doc/fdl-1.3.texi b/doc/fdl-1.3.texi
index cb71f05a175..11dc812753a 100644
--- a/doc/fdl-1.3.texi
+++ b/doc/fdl-1.3.texi
@@ -6,7 +6,7 @@
 
 @display
 Copyright @copyright{} 2000, 2001, 2002, 2007, 2008 Free Software Foundation, Inc.
-@uref{http://fsf.org/}
+@uref{https://fsf.org/}
 
 Everyone is permitted to copy and distribute verbatim copies
 of this license document, but changing it is not allowed.
@@ -414,7 +414,7 @@ The Free Software Foundation may publish new, revised versions
 of the GNU Free Documentation License from time to time.  Such new
 versions will be similar in spirit to the present version, but may
 differ in detail to address new problems or concerns.  See
-@uref{http://www.gnu.org/copyleft/}.
+@uref{https://www.gnu.org/copyleft/}.
 
 Each version of the License is given a distinguishing version number.
 If the Document specifies that a particular numbered version of this