l10n: Updated Sinhala (si) translation to 4%

New status: 31 messages complete with 2 fuzzies and 636 untranslated.

Transmitted-via: Transifex (translations.xfce.org).

po/si.po

@@ -42,8 +42,9 @@ msgstr ""
 
 #. setup application name
 #: ../thunar/main.c:124
+#, fuzzy
 msgid "Thunar"
-msgstr ""
+msgstr "Thunar"
 
 #. initialize Gtk+
 #: ../thunar/main.c:141