[Enhancement] Use a single line for "Visibility in Graph" in context-menus

[goran-w]

The "Visibility in Graph" context-menu item would be improved by using a single line (instead of two lines), since it currently looks like the first line is a normal menu-item that can be selected. A single line like this would work fine:

Visibility in Graph: <filter-icon> <hide-icon>

(Also, there could be tooltips on the icon, to clarify their meaining.)

[love-linger]

• Although this control is in the ContextMenu, it is not a regular MenuItem. Combining it into one line would instead make it be mistaken as a clickable whole (or currently disabled).
• Due to the limitations of the AvaloniaUI MenuItem control, it is currently not possible to display a tooltip for its children.

[goran-w]

I'm mistaking the upper line as a clickable one anyway. Putting the icons on the same line and adding a colon would work just as well or better IMHO, and would use up less of the space in the context menu. (Maybe also color the title different, to make it clear that it's not a standard menu-item?)

[goran-w]

Related commit: 1eb313f7d9840724075ae62d1acf01161faa7144 - Nice, the subtle changes in color and "boldness" of the item-text makes it stand out as a non-standard menu-item.

After that change, I think it would definitely work as a one-liner, with the title being followed by a colon and then the two icons.

(We could then maybe even have the eye-icon to the left of the title, for easy visual recognition and for consistency with the other items in the same submenu, which all have icons.)

[goran-w]

BTW, in the drop-down from the eye-icon under BRANCHES, the 'Unset' item could instead be called 'Clear filters' (or similar) which I think is more clarifying. (Or at least 'Unset filters'.)

[goran-w]

Here's a mockup of how it could look as a one-liner (including the eye-icon to the left of the item-title) :