Recover docs for git vendoring
authorPeter Marheine <peter@taricorp.net>
Mon, 8 Jan 2018 04:46:55 +0000 (15:46 +1100)
committerPeter Marheine <peter@taricorp.net>
Mon, 8 Jan 2018 04:46:55 +0000 (15:46 +1100)
commit12385f26ad3e306eeba79bde45aa85f9bcfe845a
tree0857855a99af6a53ad1cac6f21ed865482493ba5
parente0b4c582a1f71f884a62716f26a9db1331d16405
Recover docs for git vendoring

Cherry-picked from 5b08b8fe1019147fe489db17a9a8ae7ebe97f9e9 which failed
to update the book and was replaced in
1271bb4de0c0e0a085be239c2418af9c673ffc87.
src/doc/src/reference/source-replacement.md