Fix keyboard shortcut for New Blank Window option

Updated the keyboard shortcut for creating a new blank window to include 'Ctrl/Cmd + Shift + N'.

Signed-off-by: mr. m <91018726+mr-cheffy@users.noreply.github.com>

Author: mr-cheffy

content/docs/user-manual/window-sync.mdx

@@ -18,7 +18,7 @@ Zen now **syncs windows on the same device**, so changes in one window are refle
 Zen saves the state of all your windows when you quit, either through the "Quit" option in the main menu or by using the <KeyboardShortcut shortcut="Ctrl + Q" /> shortcut. Upon reopening Zen, all your windows will be restored without tab loss.
 
 ## New Blank Window option
-You can also create blank windows as an alternative to synced windows. A **New Blank Window** option is available from the main menu, and can be accessed using <KeyboardShortcut shortcut="Ctrl + Alt + N" /> (<KeyboardShortcut shortcut="Alt + N" /> for Windows; keyboard shortcut can be configured from Settings). Blank windows will inherit cookies and container from the origin Space, and sites you visit in blank windows will also be written to your history. 
+You can also create blank windows as an alternative to synced windows. A **New Blank Window** option is available from the main menu, and can be accessed using <KeyboardShortcut shortcut="Ctrl/Cmd + Shift + N" /> (keyboard shortcut can be configured from Settings). Blank windows will inherit cookies and container from the origin Space, and sites you visit in blank windows will also be written to your history. 
 
 For example, when you open a blank window from a Space with a Banking container profile, the new blank window will open tabs in the Banking container by default.