rebase: added comments Added comments describing the state variable and constants used throughout the rebase extension

monoblue: visually highlight source lines when hovering over line numbers Due to how the line links now reside outside of the source lines, hovering over line numbers doesn't count as hovering over the appropriate source line. It can be worked around by using a "+" css selector. However, it's necessary to reorder the elements and put <a> before <span> (which is actually quite logical). It works without further css tweaks because <a> is already absolute-positioned and so the order doesn't matter visually.

monoblue: make the size of line links bigger to cover line numbers better Due to how the line numbers in monoblue are formed (via css counters), the size of the area with the numbers and the size of the actually clickable links are not tied together well enough. Before this patch, there were noticeable "gaps" between line links - clicking on the bottom part of a visible line number did nothing as opposed to selecting this line. Let's set font-size for everything in pre.sourcelines so that it also affects the links and then add a bit of padding to them so compensate for layout differences. This way the sizes are still not 100% the same, but should be very close.