Adding explanation to translators

Some strings are missing in French at least. And some are quite
complex to understand. Especially without context, without knowledge
of Python. I tried to copy the only indication I found and add more
indication, hoping I did it correctly.

anki/stats.py

@@ -379,6 +379,7 @@ group by day order by day""" % (self._limit(), lim),
             tunit = _("hours")
         else:
             tunit = unit
+        #T: unit: can be hours, minutes, reviews... tot: the number of unit.
         self._line(i, _("Total"), _("%(tot)s %(unit)s") % dict(
             unit=tunit, tot=int(tot)))
         if convHours:
@@ -747,6 +748,7 @@ when you answer "good" on a review.''')
         return txt
 
     def _line(self, i, a, b, bold=True):
+        #T: Symbols separating first and second column in a statistics table. Eg in "Total:    3 reviews".
         colon = _(":")
         if bold:
             i.append(("<tr><td width=200 align=right>%s%s</td><td><b>%s</b></td></tr>") % (a,colon,b))
@@ -814,7 +816,13 @@ from cards where did in %s""" % self._limit())
         if xunit is None:
             conf['timeTicks'] = False
         else:
-            conf['timeTicks'] = {1: _("d"), 7: _("w"), 31: _("mo")}[xunit]
+            #T: abbreviation of day
+            d = _("d")
+            #T: abbreviation of week
+            w = _("w")
+            #T: abbreviation of month
+            mo = _("mo")
+            conf['timeTicks'] = {1: d, 7: w, 31: mo}[xunit]
         # types
         width = self.width
         height = self.height

anki/utils.py

@@ -50,11 +50,17 @@ inTimeTable = {
 
 def shortTimeFmt(type):
     return {
+#T: year is an abbreviation for year. %s is a number of years
     "years": _("%sy"),
+#T: m is an abbreviation for month. %s is a number of months
     "months": _("%smo"),
+#T: d is an abbreviation for day. %s is a number of days
     "days": _("%sd"),
+#T: h is an abbreviation for hour. %s is a number of hours
     "hours": _("%sh"),
+#T: m is an abbreviation for minute. %s is a number of minutes
     "minutes": _("%sm"),
+#T: s is an abbreviation for second. %s is a number of seconds
     "seconds": _("%ss"),
     }[type]
 

aqt/browser.py

@@ -1060,6 +1060,8 @@ by clicking on one on the left."""))
 
                 # add templates
                 for c, tmpl in enumerate(nt['tmpls']):
+                    #T: name is a card type name. n it's order in the list of card type.
+                    #T: this is shown in browser's filter, when seeing the list of card type of a note type.
                     name = _("%(n)d: %(name)s") % dict(n=c+1, name=tmpl['name'])
                     subm.addItem(name, self._filterFunc(
                         "note", nt['name'], "card", str(c+1)))