Hyphenation: add custom hyphenation rules (#7746)

The hyphenation of a word can be changed from its default
by long pressing for 3 seconds and selecting 'Hyphenate'.
These overrides are stored in a per-language file, i.e:
koreader/settings/user-German.hyph.

frontend/ui/widget/infomessage.lua

@@ -206,15 +206,16 @@ function InfoMessage:onCloseWidget()
     end
     if self.invisible then
         -- Still invisible, no setDirty needed
-        return
+        return true
     end
     if self.no_refresh_on_close then
-        return
+        return true
     end
 
     UIManager:setDirty(nil, function()
         return "ui", self[1][1].dimen
     end)
+    return true
 end
 
 function InfoMessage:onShow()