Extend/Shring start/end of a selected tag using keyboard shortcuts.
When selecting a tag on timeline, If I need to extend/shrink its start/end to a specific point in time, the normal way to do this is to mouse drag the start/end edge to the desired point on the timeline.

It would be more easier and efficient if there exist the following keyboard shortcuts:
- keyboard shortcut to move (extend/shrink) the selected tag's start edge to the current mouse's position on the timeline and another one for the end edge.
- keyboard shortcut to extend the selected tag's start edge to the nearest first untagged active point before, and the same for the end edge can be a keyboard shortcut to extend the end edge to the nearest latest untagged active point in time.
- keyboard shortcut to extend the selected tag's start edge incremently to right / left and another one for the end edge.