[fmtflags.state] clarify pre/postconditions

Author: Eisenwave

source/iostreams.tex

@@ -1207,7 +1207,7 @@
 \begin{itemdescr}
 \pnum
 \ensures
-\tcode{fmtfl == flags()}.
+\tcode{fmtfl == flags()} is \keyword{true}.
 
 \pnum
 \returns
@@ -1285,7 +1285,7 @@
 \begin{itemdescr}
 \pnum
 \ensures
-\tcode{prec == precision()}.
+\tcode{prec == precision()} is \keyword{true}.
 
 \pnum
 \returns
@@ -1313,7 +1313,7 @@
 \begin{itemdescr}
 \pnum
 \ensures
-\tcode{wide == width()}.
+\tcode{wide == width()} is \keyword{true}.
 
 \pnum
 \returns