[ostream.formatted.reqmts] Insert space around & for consistency

There exist 3 (exceptions() & badbit) in this draft, but only this one (exceptions()&badbit).

Author: Andreas-Krug

source/iostreams.tex

@@ -6360,7 +6360,7 @@
 \tcode{*this}'s
 error state.
 If
-\tcode{(exceptions()\&badbit) != 0}
+\tcode{(exceptions() \& badbit) != 0}
 then the exception is rethrown.
 Whether or not an exception is thrown, the
 \tcode{sentry}