Documentation cleanup: * Removed docs for Lexer::makeFileCharRange from Lexer.cpp, as they're in   the header file; * Reworked the documentation for SkipBlockComment so that it doesn't confuse   Doxygen's comment parsing; * Added another summary with \brief markup.
Documentation cleanup:
* Removed docs for Lexer::makeFileCharRange from Lexer.cpp, as they're in
  the header file;
* Reworked the documentation for SkipBlockComment so that it doesn't confuse
  Doxygen's comment parsing;
* Added another summary with \brief markup.


git-svn-id: ffe668792ed300d6c2daa1f6eba2e0aa28d7ec6c@158618 91177308-0d34-0410-b5e6-96231b3b80d8

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