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

[Christian Clauss via llvm-commits]

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@@ -4770,7 +4770,7 @@ void RewriteInstance::updateELFSymbolTable(
     if (!Section)
       return false;
 
-    // Remove the section symbol iif the corresponding section was stripped.
+    // Remove the section symbol if the corresponding section was stripped.
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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