Summary:
This splits out a section in the command guide for llvm tools that can be used as replacements for GNU tools. For pages that didn't exist, I added stub pages that can be individually filled in by followup patches.
Tested by running `ninja docs-llvm-html` and inspecting locally.
Reviewers: jhenderson, MaskRay, grimar, alexshap
Reviewed By: jhenderson, MaskRay, grimar
Subscribers: smeenai, arphaman, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D63014
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@363100 91177308-0d34-0410-b5e6-96231b3b80d8
