"Add tied note" while in note entry mode over rest should always tie from previous note

Your idea

When in note entry mode, with the cursor at a rest, when there is a note/chord immediately prior, then pressing "Add tied note" (T) should duplicate the note/chord at the chosen duration, and create a tie from the previous note/chord into it.

(Notably, this should happen even if there is no previous note selected).

Problem to be solved

Currently, while in note-entry mode, if the insertion point is at a rest, and the user presses T:

• If there is a selected note/chord immediately prior (from just being inserted), that whole note/chord is duplicated (with the currently chosen duration) and tied
• Otherwise nothing happens

This has three issues:

1. It doesn't work for tying into a newly created tuplet, because the note before the tuplet doesn't remain selected when the tuplet is created (so it's a bit cumbersome tying into a new tuplet)
2. It doesn't work when in note entry mode but not having just created the note before (potentially surprising, and a bit cumbersome)
3. In the case of a chord, it is not totally logical that although only one note is visually selected, the whole chord is duplicated

(I mention point 3 mostly as a counter-argument to the possible suggestion that the current behaviour is somehow connected to the idea of the currently selected note being what is tied).

Prior art

No response

Additional context

(This was originally Marc's suggestion at #34108)

Checklist

• This request follows the guidelines for reporting issues
• I have verified that this feature request has not been logged before, by searching the issue tracker for similar requests

Start by locating the note-entry implementation for the “Add tied note” command and its T shortcut. Reproduce the behavior with a rest after a note, chord, and newly created tuplet; done means the preceding note or chord is duplicated at the chosen duration and tied even when it is not selected.