[libc][obvious] Include Sqrt.h in SqrtLongDoubleX86.h.

This makes SqrtLongDoubleX86.h includable by itself.

GitOrigin-RevId: cb19e8c6d192a108b72ab07362921864a9e244f9
diff --git a/utils/FPUtil/SqrtLongDoubleX86.h b/utils/FPUtil/SqrtLongDoubleX86.h
index 2ac7304..df80d7d 100644
--- a/utils/FPUtil/SqrtLongDoubleX86.h
+++ b/utils/FPUtil/SqrtLongDoubleX86.h
@@ -10,6 +10,8 @@
 #define LLVM_LIBC_UTILS_FPUTIL_SQRT_LONG_DOUBLE_X86_H
 
 #include "FPBits.h"
+#include "Sqrt.h"
+
 #include "utils/CPP/TypeTraits.h"
 
 namespace __llvm_libc {