[istream.formatted.reqmts] clarify boolean expression

Author: Eisenwave

source/iostreams.tex

@@ -4668,7 +4668,8 @@
 If an exception is thrown during input then
 \tcode{ios_base::badbit} is set in the local error state,
 \tcode{*this}'s error state is set to the local error state, and
-the exception is rethrown if \tcode{(exceptions() \& badbit) != 0}.
+the exception is rethrown
+if \tcode{(exceptions() \& badbit) != 0} is \keyword{true}.
 After extraction is done, the input function calls \tcode{setstate}, which
 sets \tcode{*this}'s error state to the local error state, and
 may throw an exception.