Removes a child from @self.
The child must have been added with [method@HeaderBar.pack_start], [method@HeaderBar.pack_end] or [property@HeaderBar:title-widget].
the child to remove
1.0
See Implementation
Removes a child from @self.
The child must have been added with [method@HeaderBar.pack_start], [method@HeaderBar.pack_end] or [property@HeaderBar:title-widget].