[docs][llvm-ar] Fix option:: O after r375106
[docs][llvm-ar] Fix option:: O after r375106

docs-llvm-html fails => unknown option: O

There are lots of formatting issues in the file but they will be fixed by D68998.

git-svn-id: 0ff597fd157e6f4fc38580e8d64ab130330d2411@375107 91177308-0d34-0410-b5e6-96231b3b80d8

llvm-mirror/llvm,llvm-mirror/llvm,llvm-mirror/llvm,llvm-mirror/llvm,llvm-mirror/llvm,llvm-mirror/llvm,llvm-mirror/llvm,llvm-mirror/llvm,llvm-mirror/llvm