SpaceDrawer: Draw tabs so that their endpoints align
Previously, tabs were drawn with padding of 1/8 of the width of the actual tab character. However, because tabs aren't always the same width (even in the same document), this could cause their endpoints to not line up. This resolves this issue by making the padding on either side of the symbol instead proportional to the height of the tab, which is fixed for a given font size.
Before (misaligned):
After (aligned):