Guitar guide finger notation

There is a very helpful symbol for guitar fingering notation that indicates that a finger is to be used on the same string it is already on, but on a different fret, requiring the player to slide their hand up or down the neck without performing a glissando, while the finger stays on the string to guide their hand.
This "guide finger" notation is currently very difficult to achieve. One either has to use a glissando, which is only possible if the two notes are consecutive, or manipulate the "slide-in/slide-out" symbols which causes a lot of bugs (and is needlessly time-consuming).
The guide finger is indicated with a short, straight line directly to the left of the finger number slanting in the direction of the left-hand movement (up or down). Here is an example:

Since this line is always connected to a finger number, it could either be implemented in the inspector as an option for LH Guitar Fingerings or as an element in the fingering palette that can be added to any LH Guitar Fingerings.