E-book viewer: Add shortcut option for syncing

Add a shortcut option for syncing last position and annotations. The option is
only added for non-standalone viewer mode since book syncing only applies
there. No default binding is assigned.

src/pyj/read_book/shortcuts.pyj

@@ -4,6 +4,8 @@
 
 from gettext import gettext as _
 
+from read_book.globals import runtime
+
 
 def parse_key_repr(sc):
     parts = sc.split('+')
@@ -363,6 +365,14 @@ def shortcuts_definition():
     ),
 
     }
+
+    if not runtime.is_standalone_viewer:
+        ans['sync_book'] = desc(
+            v"[]",
+            'ui',
+            _('Sync last read position/annotations'),
+        )
+
     return ans
 
 

src/pyj/read_book/view.pyj

@@ -530,6 +530,8 @@ def on_handle_shortcut(self, data):
             self.toggle_read_aloud()
         elif data.name is 'reload_book':
             ui_operations.reload_book()
+        elif data.name is 'sync_book':
+            self.overlay.sync_book()
         elif data.name is 'next_section':
             self.on_next_section({'forward': True})
         elif data.name is 'previous_section':