Merge branch 'cp/textconv-cat-file'

* cp/textconv-cat-file:
git-cat-file.txt: Document --textconv
t/t8007: test textconv support for cat-file
textconv: support for cat_file
sha1_name: add get_sha1_with_context()

diff --cc builtin.h
Simple merge

diff --cc builtin/blame.c
Simple merge

diff --cc builtin/cat-file.c
Simple merge

diff --cc cache.h
Simple merge

diff --cc sha1_name.c
Simple merge