sidebar: statuses wear italic instead of an indent, and can wear colour

Three columns of indent is a fifth of a sixteen-column sidebar, spent
saying 'this belongs to the row above'. The slant says it in none: a
status now starts in the same column its tab's name starts in, and is
set in italic. That also survives the monochrome themes in contrib,
where a colour-only distinction would have had nothing to spend.

tab_status_fg / tab_status_bg are there for themes that do have colour
to spend. The fg follows tab_count when a theme does not name it -- the
same declared/derived split apply_scrolled makes -- so the six themes
in contrib get coherent status rows without a line added to any of
them. The bg is unset by default, because a band is opt-in and 'none'
is what a translucent terminal wants; the row is padded so a band that
*is* set covers the row rather than the words on it.

Two things fell out. The padding loop existed three times and is now
pad_cells. And cb_color wrote #000000 for an unset colour, so
 quietly pinned attach_bg -- 'gray
ink on the terminal's own background', says its comment -- to a black
band. Unset colours are now written commented out, the same trick the
states block uses for what it wants re-derived rather than pinned.

1 files changed, 10 insertions, 1 deletions

diff --git a/tests/test_dump_config.py b/tests/test_dump_config.py
index d6b3fd4..67679a1 100644
--- a/tests/test_dump_config.py
+++ b/tests/test_dump_config.py
@@ -106,7 +106,16 @@ def test_every_theme_colour_is_in_it():
     src = open(SRC).read()
     colours = set(re.findall(r'\{"([a-z_]+)", offsetof\(config_t', src))
     text = dump()
-    missing = sorted(c for c in colours if f"    {c} " not in text)
+    # A colour that is *unset* is the terminal's own, and a theme block has no
+    # spelling for that -- parse_color takes #rrggbb and nothing else. Those
+    # are written commented out, so the dump still names the key while loading
+    # it back does not pin "none" to black. Same tolerance the settings check
+    # above already has.
+    missing = sorted(
+        c
+        for c in colours
+        if not re.search(r"^\s*(// )?%s[ \"]" % re.escape(c), text, re.M)
+    )
     check(
         f"all {len(colours)} colours are rendered",
         not missing,