[PATCH v2 03/10] builtin.h: document SUPPORT_SUPER_PREFIX

Commit 74866d75 ("git: make super-prefix option", 2016-10-07) introduced
SUPPORT_SUPER_PREFIX as a builtin flag without documenting it. The next
patch will add another flag, so document SUPPORT_SUPER_PREFIX, thereby
bringing the documentation up to date with the available flags.

While at it, correct '3 more things to do' to '4 more things to do'.

Signed-off-by: Martin Ågren <redacted>
---
 builtin.h | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/builtin.h b/builtin.h
index 62f22b547..7bcc08456 100644
--- a/builtin.h
+++ b/builtin.h

@@ -51,9 +51,13 @@
  *	on bare repositories.
  *	This only makes sense when `RUN_SETUP` is also set.
  *
+ * `SUPPORT_SUPER_PREFIX`::
+ *
+ *	The builtin supports `--super-prefix`.
+ *
  * . Add `builtin/foo.o` to `BUILTIN_OBJS` in `Makefile`.
  *
- * Additionally, if `foo` is a new command, there are 3 more things to do:
+ * Additionally, if `foo` is a new command, there are 4 more things to do:
  *
  * . Add tests to `t/` directory.
  *

-- 
2.14.0.rc0