[m-rev.] for review: centralize recognition of sharing for tag switches

[Zoltan Somogyi]

On 2024-03-11 09:05 +11:00 AEDT, "Zoltan Somogyi" <zoltan.somogyi at runbox.com> wrote:
> For review by anyone. Peter reviewed my last diff to
> ml_tag_switch.m, so he may also want to review the diff
> that replaces that one :-(

I intend to commit this around 5pm in the absence by then
of either a review, or a promise of one.

Zoltan.