API: Add plugin_name kwarg to register_shortcut_for_widget

This is to have feature parity of kwargs with the other methods of
SpyderShortcutsMixin.

changelogs/Spyder-6.md

@@ -4,6 +4,8 @@
 
 ### API changes
 
+* Add `plugin_name` kwarg to the `register_shortcut_for_widget` method of
+  `SpyderShortcutsMixin`.
 * The `add_configuration_observer` method was added to `SpyderConfigurationObserver`.
 * Add `items_elide_mode` kwarg to the constructors of `SpyderComboBox` and
   `SpyderComboBoxWithIcons`.

spyder/api/shortcuts.py

@@ -110,6 +110,7 @@ def register_shortcut_for_widget(
         triggered: Callable,
         widget: Optional[QWidget] = None,
         context: Optional[str] = None,
+        plugin_name: Optional[str] = None,
     ):
         """
         Register a shortcut for a widget that inherits this mixin.
@@ -128,6 +129,10 @@ def register_shortcut_for_widget(
             Name of the shortcut context, e.g. "editor" for shortcuts that have
             effect when the Editor is focused or "_" for global shortcuts. If
             not set, the widget's CONF_SECTION will be used as context.
+        plugin_name: str, optional
+            Name of the plugin where the shortcut is defined. This is only
+            necessary for third-party plugins that have shortcuts with several
+            contexts.
         """
         context = self.CONF_SECTION if context is None else context
         widget = self if widget is None else widget
@@ -140,6 +145,7 @@ def register_shortcut_for_widget(
             triggered=triggered,
             context=context,
             widget=widget,
+            plugin_name=plugin_name,
         )
 
         self.add_configuration_observer(
@@ -159,6 +165,7 @@ def _register_shortcut(
         triggered: Callable,
         context: str,
         widget: QWidget,
+        plugin_name: Optional[str]
     ):
         """
         Auxiliary function to register a shortcut for a widget.
@@ -178,18 +185,22 @@ def _register_shortcut(
         context: str, optional
             Name of the shortcut context, e.g. "editor" for shortcuts that have
             effect when the Editor is focused or "_" for global shortcuts.
+        plugin_name: str, optional
+            Name of the plugin where the shortcut is defined. This is only
+            necessary for third-party plugins that have shortcuts with several
+            contexts.
         """
         # Disable current shortcut, if available
-        current_shortcut = self._shortcuts.get((context, name))
+        current_shortcut = self._shortcuts.get((context, name, plugin_name))
         if current_shortcut:
             current_shortcut.setEnabled(False)
             current_shortcut.deleteLater()
-            self._shortcuts.pop((context, name))
+            self._shortcuts.pop((context, name, plugin_name))
 
         # Create a new shortcut
         new_shortcut = QShortcut(QKeySequence(keystr), widget)
         new_shortcut.activated.connect(triggered)
         new_shortcut.setContext(Qt.WidgetWithChildrenShortcut)
 
         # Save shortcut
-        self._shortcuts[(context, name)] = new_shortcut
+        self._shortcuts[(context, name, plugin_name)] = new_shortcut