Setting the year as an ordinal number in Croatian

With this commit, the "master" version of the Statistics Chart
report will show a year as an ordinal number in Croatian.

So our translators will have until 5.1.0 is released to translate
the two new strings, in all the supported gramps languages.

Issue #10822

gramps/plugins/drawreport/statisticschart.py

@@ -421,7 +421,7 @@ class Extract:
         if date:
             year = date.get_year()
             if year:
-                return [str(year)]
+                return [self._get_date(Date(year))] # localized year
         return [_T_("Date(s) missing")]
 
     def get_month(self, event):
@@ -672,6 +672,7 @@ class Extract:
         self._locale = rlocale
         self._ = rlocale.translation.sgettext
         self._get_type = rlocale.get_type
+        self._get_date = rlocale.get_date
 
         data = []
         ext = self.extractors
@@ -788,21 +789,12 @@ class StatisticsChart(Report):
         else:
             genders = None
 
-        # needed for keyword based localization
-        mapping = {
-            'genders': genders,
-            'year_from': year_from,
-            'year_to': year_to
-        }
-
         if genders:
-            span_string = self._("%(genders)s born "
-                                 "%(year_from)04d-%(year_to)04d"
-                                ) % mapping
+            span_string = self._("%s born") % genders
         else:
-            span_string = self._("Persons born "
-                                 "%(year_from)04d-%(year_to)04d"
-                                ) % mapping
+            span_string = self._("Persons born")
+        span_string += " %s-%s" % (self._get_date(Date(year_from)), # localized
+                                   self._get_date(Date(year_to)))
 
         people = self.filter.apply(self.database,
                                    self.database.iter_person_handles(),