[PATCH] [YAML] Add new method `yaml::IO::maskedBitSetCase()` to simplify handling of bitset flags with enumeration block

[Sean Silva]

================
Comment at: docs/YamlIO.rst:418
@@ +417,3 @@
+
+To support reading and writing such fields, you need to use the maskeBitSet()
+method and provide the bit values, their names and the enumeration mask.
----------------
typo: maskeBitSet

http://reviews.llvm.org/D3807