Sphinx does not have a lexer for OpenCL, so falling back to C for the language on the code block. Also fixing an indentation warning. NFC to the content of the documentation itself.
Sphinx does not have a lexer for OpenCL, so falling back to C for the language on the code block. Also fixing an indentation warning. NFC to the content of the documentation itself.

git-svn-id: ffe668792ed300d6c2daa1f6eba2e0aa28d7ec6c@222894 91177308-0d34-0410-b5e6-96231b3b80d8

apple/swift-clang,llvm-mirror/clang,llvm-mirror/clang,llvm-mirror/clang,apple/swift-clang,apple/swift-clang,apple/swift-clang,llvm-mirror/clang,llvm-mirror/clang,llvm-mirror/clang,apple/swift-clang,llvm-mirror/clang,llvm-mirror/clang,llvm-mirror/clang,apple/swift-clang,llvm-mirror/clang,apple/swift-clang,apple/swift-clang,apple/swift-clang,apple/swift-clang