[llvm] [bolt] Fix typos discovered by codespell (PR #124726)

[Christian Clauss via llvm-commits]

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@@ -1301,7 +1301,7 @@ class BinaryFunction {
     ColdCodeSectionName = Name.str();
   }
 
-  /// Return true iif the function will halt execution on entry.
+  /// Return true if the function will halt execution on entry.
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cclauss wrote:

`iff` can be ___if-and-only-if___ but I do not sense that is the case here.

https://github.com/llvm/llvm-project/pull/124726