typo Int -> int

CppCoreGuidelines.md

@@ -560,7 +560,7 @@ Code clarity and performance. You don't need to write error handlers for errors
         static_assert(sizeof(Int) >= 4);    // do: compile-time check
 
         int bits = 0;         // don't: avoidable code
-        for (Int i = 1; i; i <<= 1)
+        for (int i = 1; i; i <<= 1)
             ++bits;
         if (bits < 32)
             cerr << "Int too small\n";