Vocabulary builder: make a word's book title changeable (#9776)

Adds the ability to re-assign which book a word belongs to
and change the name of an existing book. It can be used as
a way to regroup words and hide/show them by book.

frontend/ui/widget/sortwidget.lua

@@ -84,7 +84,7 @@ function SortItemWidget:init()
                 TextWidget:new{
                     text = self.item.text,
                     max_width = text_max_width,
-                    face = self.face,
+                    face = self.item.face or self.face,
                 },
             },
         },
@@ -98,7 +98,11 @@ function SortItemWidget:onTap(_, ges)
             self.item:callback()
         end
     elseif self.show_parent.sort_disabled then
-        return true
+        if self.item.callback then
+            self.item:callback()
+        else
+            return true
+        end
     elseif self.show_parent.marked == self.index then
         self.show_parent.marked = 0
     else
@@ -109,7 +113,9 @@ function SortItemWidget:onTap(_, ges)
 end
 
 function SortItemWidget:onHold()
-    if self.item.callback then
+    if self.item.hold_callback then
+        self.item:hold_callback(function() self.show_parent:_populateItems() end)
+    elseif self.item.callback then
         self.item:callback()
         self.show_parent:_populateItems()
     end