[clang] [llvm] Update documentation and release notes for llvm-profgen COFF support (PR #84864)

[Haohai Wen via cfe-commits]

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@@ -2434,6 +2449,15 @@ usual build cycle when using sample profilers for optimization:
    it provides better call information, which improves the accuracy of
    the profile data.
 
+   When using SEP:
+
+   .. code-block:: console
+
+     $ sep -start -ec BR_INST_RETIRED.NEAR_TAKEN:precise=yes:pdir -lbr no_filter:usr -perf-script ip,brstack -app ./code
+
+   This produces a ``perf.data.script`` output which can be used with
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HaohaiWen wrote:

Should change to code.perf.data.script if specify -out code.tb7

https://github.com/llvm/llvm-project/pull/84864