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/inputtext.lua

@@ -61,7 +61,6 @@ local InputText = InputContainer:new{
     for_measurement_only = nil, -- When the widget is a one-off used to compute text height
     do_select = false, -- to start text selection
     selection_start_pos = nil, -- selection start position
-    is_keyboard_hidden = false, -- to be able to show the keyboard again when it was hidden (by VK itself)
 }
 
 -- only use PhysicalKeyboard if the device does not have touch screen
@@ -122,11 +121,6 @@ if Device:isTouchDevice() or Device:hasDPad() then
         function InputText:onTapTextBox(arg, ges)
             if self.parent.onSwitchFocus then
                 self.parent:onSwitchFocus(self)
-            else
-                if self.is_keyboard_hidden == true then
-                    self:onShowKeyboard()
-                    self.is_keyboard_hidden = false
-                end
             end
             if #self.charlist > 0 then -- Avoid cursor moving within a hint.
                 local textwidget_offset = self.margin + self.bordersize + self.padding
@@ -569,21 +563,12 @@ end
 
 function InputText:onShowKeyboard(ignore_first_hold_release)
     Device:startTextInput()
+
     self.keyboard.ignore_first_hold_release = ignore_first_hold_release
     UIManager:show(self.keyboard)
     return true
 end
 
-function InputText:onHideKeyboard()
-    if not self.has_nav_bar then
-        UIManager:close(self.keyboard)
-        Device:stopTextInput()
-        self.is_keyboard_hidden = true
-    end
-
-    return self.is_keyboard_hiddenend
-end
-
 function InputText:onCloseKeyboard()
     UIManager:close(self.keyboard)
     Device:stopTextInput()