gh-75666: Fix Misc.unbind behaviour when funcid is given

Lib/tkinter/__init__.py

@@ -1385,11 +1385,14 @@ def bind(self, sequence=None, func=None, add=None):
         return self._bind(('bind', self._w), sequence, func, add)
 
     def unbind(self, sequence, funcid=None):
-        """Unbind for this widget for event SEQUENCE  the
-        function identified with FUNCID."""
-        self.tk.call('bind', self._w, sequence, '')
+        """Unbind for this widget the event SEQUENCE. if
+        FUNCID is given, delete the command also."""
+        bound = ''
         if funcid:
             self.deletecommand(funcid)
+            funcs = self.tk.call('bind', self._w, sequence, None).split('\n')
+            bound = '\n'.join([f for f in funcs if not f.startswith(f'if {{"[{funcid}')])
+        self.tk.call('bind', self._w, sequence, bound)
 
     def bind_all(self, sequence=None, func=None, add=None):
         """Bind to all widgets at an event SEQUENCE a call to function FUNC.

Misc/NEWS.d/next/Library/2020-01-11-22-09-29.bpo-31485.DSvjsY.rst

@@ -0,0 +1 @@
+On the tkinter library, the widget.unbind(<Sequence>, funcid) call unbinds all bindings for <Sequence>, while documentation states that when funcid is given all other bindings remains untuched. Apparently this behaviour is not offered by tkinter itself and, in case of non-empty funcid argument value be given, should be obtained by, at first, unbinding all bindings and then bind again all the ones not having the given funcid. This is basically what the proposed patch does. It takes account of the modifications done into the unbind method docstring, as described by other PSF members on the issue tracker.