Subtitles: remove choices from translated strings.

Should help the translators

modules/demux/subtitle.c

@@ -53,11 +53,7 @@ static void Close( vlc_object_t *p_this );
     N_("Override the normal frames per second settings. " \
     "This will only work with MicroDVD and SubRIP (SRT) subtitles.")
 #define SUB_TYPE_LONGTEXT \
-    N_("Force the subtiles format. Valid values are : \"microdvd\", " \
-    "\"subrip\", \"subviewer\", \"ssa1\", \"ssa2-4\", \"ass\", \"vplayer\", " \
-    "\"sami\", \"dvdsubtitle\", \"mpl2\", \"aqt\", \"pjs\", "\
-    "\"mpsub\", \"jacosub\", \"psb\", \"realtext\", \"dks\", \"subviewer1\", " \
-    " and \"auto\" (meaning autodetection, this should always work).")
+    N_("Force the subtiles format. Selecting \"auto\" means autodetection and should always work.")
 #define SUB_DESCRIPTION_LONGTEXT \
     N_("Override the default track description.")