doc: switch links to https

These sites offer https versions of their content.
Using the https versions provides some protection for users.

[j6t: cherry-picked from d05b08c]

Signed-off-by: Josh Soref <jsoref@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Johannes Sixt <j6t@kdbg.org>

Author: jsoref

git-gui.sh

@@ -24,7 +24,7 @@ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 GNU General Public License for more details.
 
 You should have received a copy of the GNU General Public License
-along with this program; if not, see <http://www.gnu.org/licenses/>.}]
+along with this program; if not, see <https://www.gnu.org/licenses/>.}]
 
 ######################################################################
 ##
@@ -3052,7 +3052,7 @@ if {$doc_path ne {}} {
 if {[file isfile $doc_path]} {
 	set doc_url "file:$doc_path"
 } else {
-	set doc_url {http://www.kernel.org/pub/software/scm/git/docs/}
+	set doc_url {https://www.kernel.org/pub/software/scm/git/docs/}
 }
 
 proc start_browser {url} {

lib/encoding.tcl

@@ -3,7 +3,7 @@
 # (Copied from gitk, commit fd8ccbec4f0161)
 
 # This list of encoding names and aliases is distilled from
-# http://www.iana.org/assignments/character-sets.
+# https://www.iana.org/assignments/character-sets.
 # Not all of them are supported by Tcl.
 set encoding_aliases {
     { ANSI_X3.4-1968 iso-ir-6 ANSI_X3.4-1986 ISO_646.irv:1991 ASCII

po/README

@@ -39,7 +39,7 @@ in your language?
 If you do not know what your language should be named, you need to find
 it.  This currently follows ISO 639-1 two letter codes:
 
-	http://www.loc.gov/standards/iso639-2/php/code_list.php
+	https://www.loc.gov/standards/iso639-2/php/code_list.php
 
 For example, if you are preparing a translation for Afrikaans, the
 language code is "af".  If there already is a translation for your