Merge branch 'ab/doc-cat-file-e-still-shows-errors' into maint

Doc update. * ab/doc-cat-file-e-still-shows-errors: cat-file doc: document that -e will return some output

Junio C Hamano committed Feb 15, 2018 at 15:18 UTC c93150cfb02257b38d0f8abcafc7de5908afbb3b

No changes.