[clang] [NFC][Clang][Headers] Update refs to ACLE in comments (PR #78305)

[James Westwood via cfe-commits]

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@@ -308,7 +313,7 @@ __qdbl(int32_t __t) {
 }
 #endif
 
-/* 9.4.3 Accumultating multiplications */
+/* 8.4.3 Accumultating multiplications */
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jwestwood921 wrote:

There is a spelling error: 'Accumultating' instead of 'Accumulating'.

https://github.com/llvm/llvm-project/pull/78305