Previously, because of the new underline styles a couple of tests were
failing due to an unexpected number of sprites being returned from the
test-set-up. No new tests were added.
Dashed underline looks pretty good regardless of conditions, but the
dotted underline only looks good/correct on certain font-sizes. This is
due to the underline being rendered on a per cell/glyph basis (so one
can not place a dot directly between two letters, say. Could be remedied
by pulling the rendering of the underlines into the shader, but that is
more work.
In `Colored and styled underlines` it's proposed that the SGR codes
\e[4:4m and \e[4:5m are used to add a dotted or dashed underline to the
rendering context respectively. This commit prepares the necessary
changes to add the two additional underline style, while still rendering
them as a normal underline and curly underline.
Joseph Adams