[docs] Tweak update to Phabricator docs about setting repository for diffs uploaded via web

Summary:
In D41919, I missed that there was a *second* step when uploading
diffs via web where the repository should be specified.

Reviewers: asb, probinson

Reviewed By: asb

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D41956

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@322375 91177308-0d34-0410-b5e6-96231b3b80d8
1 file changed