[gnome-taquin] Translate strings from about dialog.

[Arnaud B. <arnaudb src gnome org>]

commit ff9cebd0934da512ce8548e8133458d01593a5f4
Author: Arnaud Bonatti <arnaud bonatti gmail com>
Date:   Sun Aug 4 16:51:31 2019 +0200

    Translate strings from about dialog.

 src/taquin-main.vala | 25 +++++++++++++++----------
 1 file changed, 15 insertions(+), 10 deletions(-)
---
diff --git a/src/taquin-main.vala b/src/taquin-main.vala
index 9210670..dc052da 100644
--- a/src/taquin-main.vala
+++ b/src/taquin-main.vala
@@ -501,19 +501,24 @@ private class Taquin : Gtk.Application, BaseApplication
         comments = _("A classic 15-puzzle game");
 
         artists = {
-            "Abelard (Wikimedia)",
-            "Alvesgaspar (Wikimedia)",
-            "Mueller-rech.muenchen (Wikimedia)",
-            "Ruskis (Wikimedia)",
-            "Toyah (Wikimedia)",
-            /* Translators: about dialog text; in the Credits, text at the end of the "Artwork by" section */
+        /* Translators: about dialog text crediting an artist (a photograph), with the website where the 
image was published */
+            _("Abelard (Wikimedia)"), _("Alvesgaspar (Wikimedia)"), _("Mueller-rech.muenchen (Wikimedia)"),
+            _("Ruskis (Wikimedia)"), _("Toyah (Wikimedia)"),
+
+        /* Translators: about dialog text; in the Credits, text at the end of the "Artwork by" section */
             _("(see COPYING.themes for informations)")
         };
-        authors = { "Arnaud Bonatti" };
 
-        /* Translators: about dialog text */
-        copyright = "Copyright \xc2\xa9 2014-2019 – Arnaud Bonatti";  // TODO translation; autogen, to not 
change each year?
-        documenters = { "Arnaud Bonatti" };
+        /* Translators: about dialog text crediting an author */
+        authors = { _("Arnaud Bonatti") };
+
+
+        /* Translators: about dialog text crediting a maintainer; the %u are replaced with the years of 
start and end */
+        copyright = _("Copyright \xc2\xa9 %u-%u – Arnaud Bonatti").printf (2014, 2019);
+
+
+        /* Translators: about dialog text crediting a documenter */
+        documenters = { _("Arnaud Bonatti") };
         logo_icon_name = "org.gnome.Taquin";
         program_name = PROGRAM_NAME;