[Bad instructions]　On the initial kernel download PSA window, change "Press and hold the Shift key" to "Rapidly press the Shift key"

Describe the bug
On the initial kernel download PSA screen, the instructions saying to "Press and hold the Shift key" are bad.

For years I thought Mint's GRUB menu pop-up thing during boot was flaky, but I only just figured out today that it's because I was blindly following the "hold the Shift key" instructions to a T rather to the point that I would even customize GRUB so that it would always show for 1 second during boot so that I could quickly press the down arrow key on the off-chance that I need to access GRUB.

The thing is though, it never crossed my mind until today when it failed to work once but then worked the second time to instead try what I've done for years with regards to accessing BIOS/UEFI configuration and BIOS/UEFI disk boot menu: Instead of holding the key, you rapidly press the key.

The problem is that some motherboards and keyboards, for what ever reason, won't consistently perform the action in question if you hold the key during boot rather than rapidly press the key, and this is the case not just with Mint's GRUB menu but also the aforementioned BIOS/UEFI configuration and BIOS/UEFI disk boot menus.

(I can provide a video recording if desired showing failure to display GRUB when holding Shift)

Screenshots

To Reproduce
Steps to reproduce the behavior:

1. Find a PC and/or keyboard that doesn't consistently like holding keyboard keys during boot
2. Hold the shift key during boot
3. Observe how it fails to display GRUB
4. If step 3 did display GRUB, then try again. If on repeated attempts it keeps working, then start from step 1 with a different PC and/or keyboard.
5. Alternatively, reboot and rapidly press the shift key instead in order to observe how it also displays GRUB without issue.

Expected behavior
The instructions provided should be something that always consistently works, such as my suggested "rapidly press the Shift key" proposal.

UPDATE: Since it seems that even this method doesn't quite always 100% work (though seems to still have a better success rate), it may be even better to also append something like "this may not work the first time", therefore in total saying:

• Rapidly press the Shift key to show the boot menu (this may not work the first time)

Distribution:

• Linux Mint 21.3 (for GRUB display failure)
• Linux Mint 22.1 (for mintUpdate kernel PSA instructions)

Software version:

• mintUpdate 7.0.7

Additional context
I only just found out in the last year or so that holding a keyboard key to access BIOS/UEFI configuration and BIOS/UEFI disk boot menus was even a thing as I've been rapidly pressing keyboard keys to achieve this for like 2 decades now, but whenever I tried it on my own systems the results were inconsistent and unreliable unlike rapidly pressing the corresponding keyboard key. I believe it was that semi-recent discovery that allowed me to piece-together that the "hold the Shift key" for accessing GRUB was actually a case of this exact same issue.

Search the mintUpdate source for the exact "Press and hold the Shift key" text and identify the initial kernel download PSA window. Update the instruction to the proposed wording, then reopen that window to verify the displayed text.