Debugger: Remove Pdb reference when showing Pdb frames

That's because it's not easy to grasp.

spyder/plugins/debugger/widgets/framesbrowser.py

@@ -211,7 +211,9 @@ def set_from_pdb(self, pdb_stack, curindex):
     def show_pdb(self, pdb_stack, curindex):
         """Show pdb frames."""
         self._show_frames(
-            {'Pdb': pdb_stack}, _("Pdb stack"), FramesBrowserState.Debug
+            {_("Frames"): pdb_stack},
+            _("Debugger stack"),
+            FramesBrowserState.Debug,
         )
         self._persistence = 0
         self.pdb_curindex = curindex
@@ -223,8 +225,8 @@ def show_pdb(self, pdb_stack, curindex):
     def show_exception(self, etype, error, tb):
         """Set frames from exception"""
         self._show_frames(
-            {etype: tb}, _("Exception occured"),
-            FramesBrowserState.Error)
+            {etype: tb}, _("Exception occured"), FramesBrowserState.Error
+        )
         self.sig_update_actions_requested.emit()
 
     def show_captured_frames(self, stack_dict):