Filter highlights by color in highlights search (gh gH)

[ghost]

In the highlights search (gh or gH) it would be interesting to have the option to filter by colors.

Example of use case: Suppose I use the red color for definitions (hr) and I want to search for xword in all highlights. So I would do, for example: gH and then ctrl+hr (to show only red highlights) and xword (in search). This can give you the ability to search xword in a specific context (depending on your highlights/color-code scheme).

The ability to select more than one highlight color would be also interesting.

Optionally you could also add a graphical icon at the top right to select with the mouse the color of highlights that one wants to select, instead of with the keyboard.

(I know that the use of ctrl can be conflicting if someone uses ho, hj or hk so maybe using another key or simply not using those letters could be an option).