Command(s) for Set Selection to Loop

**Describe the bug**
There is no command to enable a user to set the selection in the track(s) to be the same as the loop range in the Timeline.

In contrast there are commands for setting the selection to also be the loop range.

**To Reproduce**
Steps to reproduce the behavior:
1. Right Click on the Timeline
2. Observe: command exists for "Set Loop to Selection"
3. Observe: there is no similar command for "Set Selection to Loop"
4. Transport>Looping
5. Observe: command exists for "Set Loop to Selection"
6. Observe: there is **_no_** similar command for "Set Selection to Loop"

**Expected behavior**
a) a Timeline context menu command for "Set Selection to Loop"
b) a command in Transport>Looping for "Set Selection to Loop" _(ideally with a shortcut)_
Both of which would make or change the temporal selection to be the same as the current loop range.

**Screenshots**

**Additional information (please complete the following information):**
- OS: all
- Version: Audacity 3.1.3

**Additional context**
Surely the whole point of setting and refining a loop region in the Timeline is so that the user can then work with and edit that loop - and that requires an accurate selection.

Sure there is a workaround, relying on the use of the snap guides with the cursor in the track as you move the cursor close to the loop start and end.

This enhancement request was prompted by this user post on the Forum:
https://forum.audacityteam.org/viewtopic.php?f=46&t=122612&p=443131

Flagged for @Tantacrul as a UX/design issue

Start by locating the existing “Set Loop to Selection” command in the Timeline context menu and Transport > Looping, then trace how those menus and timeline selection are wired. Done means both requested locations provide “Set Selection to Loop,” the selection matches the current loop range, and a shortcut is included if the command system supports one.

Written by the indexing model from the issue text.