Footnotes: fix current link being unhighlight in some cases

When a link is covered by the footnote widget, we highlight it
again when closing the footnote, and schedule an unhighlight
0.5s later.
When we tap on another footnote link, this was happening too
but the unhighlight unhighlighted all, including the new
footnote link.
This disable the former when the latter happens.

frontend/apps/reader/modules/readerlink.lua

@@ -1016,6 +1016,7 @@ function ReaderLink:showAsFootnotePopup(link, neglect_current_location)
     -- (which might not be seen when covered by FootnoteWidget)
     local close_callback = nil
     if link.from_xpointer then -- coherent xpointer
+        self.ui.document:highlightXPointer() -- clear any previous one
         self.ui.document:highlightXPointer(link.from_xpointer)
         UIManager:setDirty(self.dialog, "ui")
         close_callback = function(footnote_height)
@@ -1055,10 +1056,14 @@ function ReaderLink:showAsFootnotePopup(link, neglect_current_location)
             UIManager:close(popup)
             self:onGotoLink(link, neglect_current_location)
         end,
-        on_tap_close_callback = function(arg, ges)
-            -- on tap outside, see if we are tapping on another footnote,
+        on_tap_close_callback = function(arg, ges, footnote_height)
+            -- On tap outside, see if we are tapping on another footnote,
             -- and display it if we do (avoid the need for 2 taps)
-            self:onTap(arg, ges)
+            if not self:onTap(arg, ges) then
+                -- If we did tap on another link, onTap has already cleared our
+                -- highlight. If not, call close_callback to unhighlight it.
+                close_callback(footnote_height)
+            end
         end,
         dialog = self.dialog,
     }

frontend/ui/widget/footnotewidget.lua

@@ -289,9 +289,6 @@ function FootnoteWidget:onShow()
 end
 
 function FootnoteWidget:onCloseWidget()
-    if self.close_callback then
-        self.close_callback(self.height)
-    end
     UIManager:setDirty(self.dialog, function()
         return "partial", self.container.dimen
     end)
@@ -310,7 +307,9 @@ function FootnoteWidget:onTapClose(arg, ges)
         -- it. This avoids having to tap 2 times to
         -- see another footnote.
         if self.on_tap_close_callback then
-            self.on_tap_close_callback(arg, ges)
+            self.on_tap_close_callback(arg, ges, self.height)
+        elseif self.close_callback then
+            self.close_callback(self.height)
         end
         return true
     end
@@ -320,6 +319,9 @@ end
 function FootnoteWidget:onSwipeFollow(arg, ges)
     if ges.direction == "west" then
         if self.follow_callback then
+            if self.close_callback then
+                self.close_callback(self.height)
+            end
             return self.follow_callback()
         end
     elseif ges.direction == "south" or ges.direction == "east" then
@@ -328,6 +330,9 @@ function FootnoteWidget:onSwipeFollow(arg, ges)
         -- work only when started outside the footnote.
         -- Also allow closing with swipe east (like we do to go back
         -- from link)
+        if self.close_callback then
+            self.close_callback(self.height)
+        end
         self:onClose()
         return true
     elseif ges.direction == "north" then