We are removing the "-a" command line argument in 22.0. Remove from IUG and add note to relnotes

[dyaandys]

There is no need to announce this in the 21.0 relnotes

-a means "Start in User Mode". We do not believe that anyone is using this, so let's get rid.

Appears in (at least)
windows-installation-and-configuration-guide/apl-command-line/#command-line
could it appear in a UNIX guide ?

A note about the removal should be added to the 22.0 relnotes

[dyaandys]

See mantis 23215

[FionaDyalog]

For Dyalog v22.0, this needs to be removed from Table 2 on https://docs.dyalog.com/21.0/unix-user-guide/starting-apl/ (also check examples in the Dyalog for Unix UI Guide for mentions, and update as required) and included in the Release Notes. No pre-warning of the removal required for Dyalog v21.0.

The Dyalog v22.0 Release Notes will be updated for this under #1141