Update libsolutil/CommonIO.cpp

Co-authored-by: Kamil Śliwak <kamil.sliwak@codepoets.it>

Author: chriseth

libsolutil/CommonIO.cpp

@@ -84,7 +84,7 @@ string solidity::util::readBytes(istream& _input, size_t _length)
 	string output;
 	output.resize(_length);
 	_input.read(output.data(), static_cast<streamsize>(_length));
-	// If read() reads fewer bytes it sets falibit.
+	// If read() reads fewer bytes it sets failbit in addition to eofbit.
 	if (_input.fail())
 		output.resize(static_cast<size_t>(_input.gcount()));
 	return output;