These are used in revision.c. After the last patch they are replaced
with the refs_ version. Delete them (except for_each_remote_ref_submodule
which is still used by submodule.c)

Signed-off-by: Nguyễn Thái Ngọc Duy <redacted>
---
 Documentation/technical/api-ref-iteration.txt |  7 ++-----
 refs.c                                        | 29 ---------------------------
 refs.h                                        |  9 ---------
 3 files changed, 2 insertions(+), 43 deletions(-)

diff --git a/Documentation/technical/api-ref-iteration.txt b/Documentation/technical/api-ref-iteration.txt
index 37379d8337..c9e9a60dbd 100644
--- a/Documentation/technical/api-ref-iteration.txt
+++ b/Documentation/technical/api-ref-iteration.txt

@@ -32,11 +32,8 @@ Iteration functions
 
 * `for_each_glob_ref_in()` the previous and `for_each_ref_in()` combined.
 
-* `head_ref_submodule()`, `for_each_ref_submodule()`,
-  `for_each_ref_in_submodule()`, `for_each_tag_ref_submodule()`,
-  `for_each_branch_ref_submodule()`, `for_each_remote_ref_submodule()`
-  do the same as the functions described above but for a specified
-  submodule.
+* Use `refs_` API for accessing submodules. The submodule ref store could
+  be obtained with `get_submodule_ref_store().