[UX] Gesture manager: allow folder shortcuts as action in Reader (#4759)

Note that `self.ui:onClose()` properly closes open documents. There might be similar pieces of code around that don't do that.

Fixes #4755.

frontend/apps/reader/readerui.lua

@@ -13,6 +13,7 @@ local Event = require("ui/event")
 local FileManagerBookInfo = require("apps/filemanager/filemanagerbookinfo")
 local FileManagerHistory = require("apps/filemanager/filemanagerhistory")
 local FileManagerFileSearcher = require("apps/filemanager/filemanagerfilesearcher")
+local FileManagerShortcuts = require("apps/filemanager/filemanagershortcuts")
 local InfoMessage = require("ui/widget/infomessage")
 local InputContainer = require("ui/widget/container/inputcontainer")
 local InputDialog = require("ui/widget/inputdialog")
@@ -336,6 +337,11 @@ function ReaderUI:init()
         dialog = self.dialog,
         ui = self,
     })
+    -- folder shortcuts
+    self:registerModule("folder_shortcuts", FileManagerShortcuts:new{
+        dialog = self.dialog,
+        ui = self,
+    })
     -- history view
     self:registerModule("history", FileManagerHistory:new{
         dialog = self.dialog,