Update supported compiler list. Patch by Mikael Lyngvig!

git-svn-id: https://llvm.org/svn/llvm-project/lld/trunk@196055 91177308-0d34-0410-b5e6-96231b3b80d8
Fix "doesnot", "endsup" typos and "lets" grammar issues

git-svn-id: https://llvm.org/svn/llvm-project/lld/trunk@196056 91177308-0d34-0410-b5e6-96231b3b80d8