Add shortcuts for New Script and New Text File in the script editor

These default to Ctrl + N and Ctrl + Shift + N respectively,
and will only work while the script editor is focused.
When the script editor is not focused, a new scene
(or inherited scene) will be created instead.

editor/plugins/script_editor_plugin.cpp

@@ -3697,8 +3697,8 @@ ScriptEditor::ScriptEditor(EditorNode *p_editor) {
 	file_menu->set_shortcut_context(this);
 	menu_hb->add_child(file_menu);
 
-	file_menu->get_popup()->add_shortcut(ED_SHORTCUT("script_editor/new", TTR("New Script...")), FILE_NEW);
-	file_menu->get_popup()->add_shortcut(ED_SHORTCUT("script_editor/new_textfile", TTR("New Text File...")), FILE_NEW_TEXTFILE);
+	file_menu->get_popup()->add_shortcut(ED_SHORTCUT("script_editor/new", TTR("New Script..."), KeyModifierMask::CMD | Key::N), FILE_NEW);
+	file_menu->get_popup()->add_shortcut(ED_SHORTCUT("script_editor/new_textfile", TTR("New Text File..."), KeyModifierMask::CMD | KeyModifierMask::SHIFT | Key::N), FILE_NEW_TEXTFILE);
 	file_menu->get_popup()->add_shortcut(ED_SHORTCUT("script_editor/open", TTR("Open...")), FILE_OPEN);
 	file_menu->get_popup()->add_shortcut(ED_SHORTCUT("script_editor/reopen_closed_script", TTR("Reopen Closed Script"), KeyModifierMask::CMD | KeyModifierMask::SHIFT | Key::T), FILE_REOPEN_CLOSED);
 	file_menu->get_popup()->add_submenu_item(TTR("Open Recent"), "RecentScripts", FILE_OPEN_RECENT);