Description
In v8.42 optional block-navigation (with highlighting of changes) was added (#616 , #717, #750).
However, this feature can be improved and made more consistent with similar functionality in other diff tools like WinMerge, P4Merge, Plastic SCM etc, by adding 2 additional buttons for first/last change-block (only visible in block-nav mode) and disabling the wrapping-around of the prev/next block-nav (which is then no longer needed, since we can quickly jump to the top/bottom change by the new buttons).
NOTE: Disabling the automatic wrapping is crucial. I find it confusing me and making me lose track, since I use the block navigation mode to step through each diff block and make sure I've checked them all. I expect the stepping to stop when I get to the end, and the current/total number shows me where I am in the sequence.
Of course, ideally the first/prev and next/last buttons should be disabled (grayed-out) when already at the top or bottom, respectively, but even without that enhancement the above described improvement would still make sense.