[PATCH] Add documentation for sample profiling support.

[Richard Smith]

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Comment at: docs/UsersManual.rst:1126
@@ +1125,3 @@
+
+   This will read ``perf.data``, the binary file ``./code`` and emit
+   the profile data in ``code.prof``. Note that if you ran ``perf``
----------------
This will read ``perf.data`` and the binary file ``./code``, and emit

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Comment at: docs/UsersManual.rst:1163
@@ +1162,3 @@
+
+The file may contain blank lines between sections and lines within a
+section. However, the spacing within a single line is fixed. Additional
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Maybe drop the second "lines" here?

http://reviews.llvm.org/D3402

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