Impossible to display "Del" and "Insert" as MenuItem accelerator

[guiv42]

Describe the bug
In a Linux app, I'm using "Del" and "Insert" keys as accelerators for some menu items, and there's no way to have these keys displayed.

To Reproduce
Call org.eclipse.swt.widgets.MenuItem.setText(), with menu item text and accelerator separated by "\t" character as described in the documentation.

Expected behavior
In menu item, accelerator is displayed (right-aligned) next to menu item text.
E.g. it works normally for a simple accelerator like "X", but it cannot work with "Del" or "Insert" keys

Screenshots
None

Environment:

1. Select the platform(s) on which the behavior is seen:

• • All OS
• • Windows
• • Linux
• • macOS

note: I did not check on other platforms, problem may be present as well.

2. Additional OS info (e.g. OS version, Linux Desktop, etc)
   tested on Linux openSuse tumbleweed

3. JRE/JDK version
   java-21-openjdk

Version since
Reproduced with SWT version 4.26.
Issue is still present in most recent code base when writing this (see analysis below)

Workaround (or) Additional context
Analysis of the current implementation, the only valid strings for an accelerator in a menu item are:

• "Enter"
• single character strings
• "Fx", with "x" a digit between 0 and 9
• "F1x", with "x" a digit between 0 and 5

And "Del" and "Insert" key do not match these patterns, so such accelerators cannot be displayed.
I did not test explicitly, but issue should also be present for other keys (e.g. "Esc")